TY  - JOUR
AU  - Dubajić, Miloš
AU  - Daničić, Aleksandar
AU  - Vuković, Nikola
AU  - Milanović, Vitomir B.
AU  - Radovanović, Jelena V.
PY  - 2018
UR  - http://link.springer.com/10.1007/s11082-018-1639-1
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/7895
AB  - In this work we theoretically investigate a possibility to use cubic nitride based multi-layer periodic nanostructure as a semiconductor metamaterial. The structure design is based on an active region of a quantum cascade laser optimized to achieve optical gain in the Terahertz (THz) spectral range. In particular, we test the GaN/AlGaN quantum well configurations, which should exhibit important advantages compared to GaAs-based structures, namely room temperature operation without the assistance of magnetic field and lower doping densities. Our numerical rate-equations model is solved self-consistently and it takes into account electron-longitudinal optical phonon scattering between all the relevant states among the adjacent periods of the structure. A global optimization routine, specifically genetic algorithm is then used to generate new gain-optimized structures. This work confirms the advantages of cubic GaN designs over GaAs ones, namely feasibility of negative refraction at room temperature without the assistance of magnetic field while keeping the doping densities of the same order of magnitude. © 2018, Springer Science+Business Media, LLC, part of Springer Nature.
T2  - Optical and Quantum Electronics
T1  - Optimization of cubic GaN/AlGaN quantum cascade structures for negative refraction in the THz spectral range
VL  - 50
IS  - 10
SP  - 373
DO  - 10.1007/s11082-018-1639-1
ER  - 

@article{
author = "Dubajić, Miloš and Daničić, Aleksandar and Vuković, Nikola and Milanović, Vitomir B. and Radovanović, Jelena V.",
year = "2018",
abstract = "In this work we theoretically investigate a possibility to use cubic nitride based multi-layer periodic nanostructure as a semiconductor metamaterial. The structure design is based on an active region of a quantum cascade laser optimized to achieve optical gain in the Terahertz (THz) spectral range. In particular, we test the GaN/AlGaN quantum well configurations, which should exhibit important advantages compared to GaAs-based structures, namely room temperature operation without the assistance of magnetic field and lower doping densities. Our numerical rate-equations model is solved self-consistently and it takes into account electron-longitudinal optical phonon scattering between all the relevant states among the adjacent periods of the structure. A global optimization routine, specifically genetic algorithm is then used to generate new gain-optimized structures. This work confirms the advantages of cubic GaN designs over GaAs ones, namely feasibility of negative refraction at room temperature without the assistance of magnetic field while keeping the doping densities of the same order of magnitude. © 2018, Springer Science+Business Media, LLC, part of Springer Nature.",
journal = "Optical and Quantum Electronics",
title = "Optimization of cubic GaN/AlGaN quantum cascade structures for negative refraction in the THz spectral range",
volume = "50",
number = "10",
pages = "373",
doi = "10.1007/s11082-018-1639-1"
}

Dubajić, M., Daničić, A., Vuković, N., Milanović, V. B.,& Radovanović, J. V.. (2018). Optimization of cubic GaN/AlGaN quantum cascade structures for negative refraction in the THz spectral range. in Optical and Quantum Electronics, 50(10), 373.
https://doi.org/10.1007/s11082-018-1639-1

Dubajić M, Daničić A, Vuković N, Milanović VB, Radovanović JV. Optimization of cubic GaN/AlGaN quantum cascade structures for negative refraction in the THz spectral range. in Optical and Quantum Electronics. 2018;50(10):373.
doi:10.1007/s11082-018-1639-1 .

Dubajić, Miloš, Daničić, Aleksandar, Vuković, Nikola, Milanović, Vitomir B., Radovanović, Jelena V., "Optimization of cubic GaN/AlGaN quantum cascade structures for negative refraction in the THz spectral range" in Optical and Quantum Electronics, 50, no. 10 (2018):373,
https://doi.org/10.1007/s11082-018-1639-1 . .

TY  - JOUR
AU  - Daničić, Aleksandar
AU  - Radovanović, Jelena V.
AU  - Ramović, Sabina
AU  - Milanović, Vitomir B.
PY  - 2016
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/927
AB  - In order to avoid losses in metamaterial unit cells at frequencies of interest, caused by metallic inclusions, an active medium design has been proposed. As candidate structures for this active medium, we have chosen quantum cascade lasers because of their high output gain. Here we analyze and compare two quantum cascade structures that emit at 4.6 THz and 3.9 THz, respectively, placed under the influence of a strong magnetic field. We first solve the full system of rate equations for all relevant Landau levels, and obtain the necessary information about carrier distribution among the levels, after which we are able to evaluate the permittivity component along the growth direction of the structure. With these data one can determine the conditions under which negative refraction occurs, and calculate the values of the refractive index of the structure, as well as the range of frequencies at which the structure exhibits negative refraction for a predefined total electron sheet density.
PB  - IOP Publishing Ltd
T2  - Journal of Physics. D: Applied Physics
T1  - Exploring negative refraction conditions for quantum cascade semiconductor metamaterials in the terahertz spectral range
VL  - 49
IS  - 8
DO  - 10.1088/0022-3727/49/8/085105
ER  - 

@article{
author = "Daničić, Aleksandar and Radovanović, Jelena V. and Ramović, Sabina and Milanović, Vitomir B.",
year = "2016",
abstract = "In order to avoid losses in metamaterial unit cells at frequencies of interest, caused by metallic inclusions, an active medium design has been proposed. As candidate structures for this active medium, we have chosen quantum cascade lasers because of their high output gain. Here we analyze and compare two quantum cascade structures that emit at 4.6 THz and 3.9 THz, respectively, placed under the influence of a strong magnetic field. We first solve the full system of rate equations for all relevant Landau levels, and obtain the necessary information about carrier distribution among the levels, after which we are able to evaluate the permittivity component along the growth direction of the structure. With these data one can determine the conditions under which negative refraction occurs, and calculate the values of the refractive index of the structure, as well as the range of frequencies at which the structure exhibits negative refraction for a predefined total electron sheet density.",
publisher = "IOP Publishing Ltd",
journal = "Journal of Physics. D: Applied Physics",
title = "Exploring negative refraction conditions for quantum cascade semiconductor metamaterials in the terahertz spectral range",
volume = "49",
number = "8",
doi = "10.1088/0022-3727/49/8/085105"
}

Daničić, A., Radovanović, J. V., Ramović, S.,& Milanović, V. B.. (2016). Exploring negative refraction conditions for quantum cascade semiconductor metamaterials in the terahertz spectral range. in Journal of Physics. D: Applied Physics
IOP Publishing Ltd., 49(8).
https://doi.org/10.1088/0022-3727/49/8/085105

Daničić A, Radovanović JV, Ramović S, Milanović VB. Exploring negative refraction conditions for quantum cascade semiconductor metamaterials in the terahertz spectral range. in Journal of Physics. D: Applied Physics. 2016;49(8).
doi:10.1088/0022-3727/49/8/085105 .

Daničić, Aleksandar, Radovanović, Jelena V., Ramović, Sabina, Milanović, Vitomir B., "Exploring negative refraction conditions for quantum cascade semiconductor metamaterials in the terahertz spectral range" in Journal of Physics. D: Applied Physics, 49, no. 8 (2016),
https://doi.org/10.1088/0022-3727/49/8/085105 . .

TY  - JOUR
AU  - Daničić, Aleksandar
AU  - Radovanović, Jelena V.
AU  - Milanović, Vitomir B.
AU  - Indjin, Dragan
AU  - Ikonić, Zoran
PY  - 2016
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/1102
AB  - We consider the influence of additional carrier confinement, achieved by application of strong perpendicular magnetic field, on inter Landau levels electron relaxation rates and the optical gain, of two different GaAs quantum cascade laser structures operating in the terahertz spectral range. Breaking of the in-plane energy dispersion and the formation of discrete energy levels is an efficient mechanism for eventual quenching of optical phonon emission and obtaining very long electronic lifetime in the relevant laser state. We employ our detailed model for calculating the electron relaxation rates (due to interface roughness and electron-longitudinal optical phonon scattering), and solve a full set of rate equations to evaluate the carrier distribution over Landau levels. The numerical simulations are performed for three- and four-well (per period) based structures that operate at 3.9 THz and 1.9 THz, respectively, both implemented in GaAs/Al0.15Ga0.85As. Numerical results are presented for magnetic field values from 1.5 T up to 20 T, while the band nonparabolicity is accounted for. (C) 2016 Elsevier B.V. All rights reserved.
PB  - Elsevier
T2  - Physica E: Low-dimensional Systems and Nanostructures
T1  - Magnetic field effects on THz quantum cascade laser: A comparative analysis of three and four quantum well based active region design
VL  - 81
SP  - 275
EP  - 280
DO  - 10.1016/j.physe.2016.03.019
ER  - 

@article{
author = "Daničić, Aleksandar and Radovanović, Jelena V. and Milanović, Vitomir B. and Indjin, Dragan and Ikonić, Zoran",
year = "2016",
abstract = "We consider the influence of additional carrier confinement, achieved by application of strong perpendicular magnetic field, on inter Landau levels electron relaxation rates and the optical gain, of two different GaAs quantum cascade laser structures operating in the terahertz spectral range. Breaking of the in-plane energy dispersion and the formation of discrete energy levels is an efficient mechanism for eventual quenching of optical phonon emission and obtaining very long electronic lifetime in the relevant laser state. We employ our detailed model for calculating the electron relaxation rates (due to interface roughness and electron-longitudinal optical phonon scattering), and solve a full set of rate equations to evaluate the carrier distribution over Landau levels. The numerical simulations are performed for three- and four-well (per period) based structures that operate at 3.9 THz and 1.9 THz, respectively, both implemented in GaAs/Al0.15Ga0.85As. Numerical results are presented for magnetic field values from 1.5 T up to 20 T, while the band nonparabolicity is accounted for. (C) 2016 Elsevier B.V. All rights reserved.",
publisher = "Elsevier",
journal = "Physica E: Low-dimensional Systems and Nanostructures",
title = "Magnetic field effects on THz quantum cascade laser: A comparative analysis of three and four quantum well based active region design",
volume = "81",
pages = "275-280",
doi = "10.1016/j.physe.2016.03.019"
}

Daničić, A., Radovanović, J. V., Milanović, V. B., Indjin, D.,& Ikonić, Z.. (2016). Magnetic field effects on THz quantum cascade laser: A comparative analysis of three and four quantum well based active region design. in Physica E: Low-dimensional Systems and Nanostructures
Elsevier., 81, 275-280.
https://doi.org/10.1016/j.physe.2016.03.019

Daničić A, Radovanović JV, Milanović VB, Indjin D, Ikonić Z. Magnetic field effects on THz quantum cascade laser: A comparative analysis of three and four quantum well based active region design. in Physica E: Low-dimensional Systems and Nanostructures. 2016;81:275-280.
doi:10.1016/j.physe.2016.03.019 .

Daničić, Aleksandar, Radovanović, Jelena V., Milanović, Vitomir B., Indjin, Dragan, Ikonić, Zoran, "Magnetic field effects on THz quantum cascade laser: A comparative analysis of three and four quantum well based active region design" in Physica E: Low-dimensional Systems and Nanostructures, 81 (2016):275-280,
https://doi.org/10.1016/j.physe.2016.03.019 . .

TY  - CONF
AU  - Ivanović, Marija D.
AU  - Petrović, Jovana S.
AU  - Miletić, Marjan
AU  - Daničić, Aleksandar
AU  - Bojović, Boško
AU  - Vukcevic, M.
AU  - Lazovic, B.
AU  - Gluvić, Zoran
AU  - Hadžievski, Ljupčo
AU  - Allsop, Thomas P.
AU  - Webb, David J.
PY  - 2015
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/7097
AB  - Non-invasive ventilation performed through an oronasal mask is a standard in clinical and homecare mechanical ventilation. Besides all its advantages, inevitable leaks through the mask cause errors in the feedback information provided by the airflow sensor and, hence, patient-ventilator asynchrony with multiple negative consequences. Here we investigate a new way to provide a trigger to the ventilator. The method is based on the measurement of rib cage movement at the onset of inspiration and during breathing by fibre-optic sensors. In a series of simultaneous measurements by a long-period fibre grating sensor and pneumotachograph we provide the statistical evidence of the 200 ms lag of the pneumo with respect the fibre-optic signal. The lag is registered consistently across three independent delay metrics. Further, we discuss exceptions from this trend and identify the needed improvements to the proposed fibre-sensing scheme.
T1  - Rib-Cage-Movement Measurements as a Potential New Trigger Signal in Non-Invasive Mechanical Ventilation
SP  - 4511
EP  - 4514
UR  - https://hdl.handle.net/21.15107/rcub_vinar_7097
ER  - 

@conference{
author = "Ivanović, Marija D. and Petrović, Jovana S. and Miletić, Marjan and Daničić, Aleksandar and Bojović, Boško and Vukcevic, M. and Lazovic, B. and Gluvić, Zoran and Hadžievski, Ljupčo and Allsop, Thomas P. and Webb, David J.",
year = "2015",
abstract = "Non-invasive ventilation performed through an oronasal mask is a standard in clinical and homecare mechanical ventilation. Besides all its advantages, inevitable leaks through the mask cause errors in the feedback information provided by the airflow sensor and, hence, patient-ventilator asynchrony with multiple negative consequences. Here we investigate a new way to provide a trigger to the ventilator. The method is based on the measurement of rib cage movement at the onset of inspiration and during breathing by fibre-optic sensors. In a series of simultaneous measurements by a long-period fibre grating sensor and pneumotachograph we provide the statistical evidence of the 200 ms lag of the pneumo with respect the fibre-optic signal. The lag is registered consistently across three independent delay metrics. Further, we discuss exceptions from this trend and identify the needed improvements to the proposed fibre-sensing scheme.",
title = "Rib-Cage-Movement Measurements as a Potential New Trigger Signal in Non-Invasive Mechanical Ventilation",
pages = "4511-4514",
url = "https://hdl.handle.net/21.15107/rcub_vinar_7097"
}

Ivanović, M. D., Petrović, J. S., Miletić, M., Daničić, A., Bojović, B., Vukcevic, M., Lazovic, B., Gluvić, Z., Hadžievski, L., Allsop, T. P.,& Webb, D. J.. (2015). Rib-Cage-Movement Measurements as a Potential New Trigger Signal in Non-Invasive Mechanical Ventilation. , 4511-4514.
https://hdl.handle.net/21.15107/rcub_vinar_7097

Ivanović MD, Petrović JS, Miletić M, Daničić A, Bojović B, Vukcevic M, Lazovic B, Gluvić Z, Hadžievski L, Allsop TP, Webb DJ. Rib-Cage-Movement Measurements as a Potential New Trigger Signal in Non-Invasive Mechanical Ventilation. 2015;:4511-4514.
https://hdl.handle.net/21.15107/rcub_vinar_7097 .

Ivanović, Marija D., Petrović, Jovana S., Miletić, Marjan, Daničić, Aleksandar, Bojović, Boško, Vukcevic, M., Lazovic, B., Gluvić, Zoran, Hadžievski, Ljupčo, Allsop, Thomas P., Webb, David J., "Rib-Cage-Movement Measurements as a Potential New Trigger Signal in Non-Invasive Mechanical Ventilation" (2015):4511-4514,
https://hdl.handle.net/21.15107/rcub_vinar_7097 .

TY  - CONF
AU  - Ivanović, M. D.
AU  - Petrović, Jovana
AU  - Daničić, Aleksandar
AU  - Miletić, Marjan
AU  - Vukčević, Miodrag
AU  - Bojović, Boško
AU  - Hadžievski, Ljupčo
AU  - Allsop, Thomas
AU  - Webb, D. J.
PY  - 2015
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/12011
AB  - In the current clinical practice of non-invasive mechanical ventilation (NIV), continuous monitoring of respiratory volumes is based on the measurement of air flow through an oronasal mask or mouthpiece. Errors in respiratory-volumes monitoring and patientventilator asynchrony due to the inevitable air leaks from the mask may lead to insufficient ventilation and/or damage of the airway system. Therefore, clinician’s observations of the chest wall expansions are required, but they are subjective, time consuming and strongly dependent on clinician’s experience [1]. We present and validate a method for the measurement of respiratory volumes by a single long period fibre-grating (LPG) sensor of bending. This method is grounded on the hypothesis that the volume of the inhaled air can be correlated with the change in a local torso curvature in a ribs area with stiff underlying tissues. Here, we explain the working principle of the LPG sensors, a monochromatic interrogation scheme, a two-step calibration-test measurement procedure and present results that establish a linear correlation between the change in the local rib-cage curvature and the change in the lung volume. Results also show good sensor accuracy in measurements of tidal and minute respiratory volumes for all clinically relevant breathing volumes [2]. Additionally, we examine the possibility of using the rib-cage movement signal measured by a single LPG sensor as a new way to provide a trigger to the ventilator. Our preliminary results on healthy volunteers provide the statistical evidence of the 200 ms lag of the pneumotechometer with respect to the fibre-optic signal. The proposed single-sensor method is non-invasive, simple, low-cost and easy to implement. Moreover this method does not suffer from the flaws of air-flow measurements, it eliminates the need for chest movement observation by clinicians and can be implemented on both male and female patients. The preliminary results are promising and indicate that the method proposed here could be used in NIV.
PB  - Belgrade : Vinča Institute of Nuclear Sciences
C3  - PHOTONICA2015 : 5th International School and Conference on Photonics and COST actions: MP1204, BM1205 and MP1205 : book of abstracts; August 24-28, 2015; Belgrade
T1  - A long-period fibre grating sensor for respiratory monitoring
SP  - 168
EP  - 168
UR  - https://hdl.handle.net/21.15107/rcub_vinar_12011
ER  - 

@conference{
author = "Ivanović, M. D. and Petrović, Jovana and Daničić, Aleksandar and Miletić, Marjan and Vukčević, Miodrag and Bojović, Boško and Hadžievski, Ljupčo and Allsop, Thomas and Webb, D. J.",
year = "2015",
abstract = "In the current clinical practice of non-invasive mechanical ventilation (NIV), continuous monitoring of respiratory volumes is based on the measurement of air flow through an oronasal mask or mouthpiece. Errors in respiratory-volumes monitoring and patientventilator asynchrony due to the inevitable air leaks from the mask may lead to insufficient ventilation and/or damage of the airway system. Therefore, clinician’s observations of the chest wall expansions are required, but they are subjective, time consuming and strongly dependent on clinician’s experience [1]. We present and validate a method for the measurement of respiratory volumes by a single long period fibre-grating (LPG) sensor of bending. This method is grounded on the hypothesis that the volume of the inhaled air can be correlated with the change in a local torso curvature in a ribs area with stiff underlying tissues. Here, we explain the working principle of the LPG sensors, a monochromatic interrogation scheme, a two-step calibration-test measurement procedure and present results that establish a linear correlation between the change in the local rib-cage curvature and the change in the lung volume. Results also show good sensor accuracy in measurements of tidal and minute respiratory volumes for all clinically relevant breathing volumes [2]. Additionally, we examine the possibility of using the rib-cage movement signal measured by a single LPG sensor as a new way to provide a trigger to the ventilator. Our preliminary results on healthy volunteers provide the statistical evidence of the 200 ms lag of the pneumotechometer with respect to the fibre-optic signal. The proposed single-sensor method is non-invasive, simple, low-cost and easy to implement. Moreover this method does not suffer from the flaws of air-flow measurements, it eliminates the need for chest movement observation by clinicians and can be implemented on both male and female patients. The preliminary results are promising and indicate that the method proposed here could be used in NIV.",
publisher = "Belgrade : Vinča Institute of Nuclear Sciences",
journal = "PHOTONICA2015 : 5th International School and Conference on Photonics and COST actions: MP1204, BM1205 and MP1205 : book of abstracts; August 24-28, 2015; Belgrade",
title = "A long-period fibre grating sensor for respiratory monitoring",
pages = "168-168",
url = "https://hdl.handle.net/21.15107/rcub_vinar_12011"
}

Ivanović, M. D., Petrović, J., Daničić, A., Miletić, M., Vukčević, M., Bojović, B., Hadžievski, L., Allsop, T.,& Webb, D. J.. (2015). A long-period fibre grating sensor for respiratory monitoring. in PHOTONICA2015 : 5th International School and Conference on Photonics and COST actions: MP1204, BM1205 and MP1205 : book of abstracts; August 24-28, 2015; Belgrade
Belgrade : Vinča Institute of Nuclear Sciences., 168-168.
https://hdl.handle.net/21.15107/rcub_vinar_12011

Ivanović MD, Petrović J, Daničić A, Miletić M, Vukčević M, Bojović B, Hadžievski L, Allsop T, Webb DJ. A long-period fibre grating sensor for respiratory monitoring. in PHOTONICA2015 : 5th International School and Conference on Photonics and COST actions: MP1204, BM1205 and MP1205 : book of abstracts; August 24-28, 2015; Belgrade. 2015;:168-168.
https://hdl.handle.net/21.15107/rcub_vinar_12011 .

Ivanović, M. D., Petrović, Jovana, Daničić, Aleksandar, Miletić, Marjan, Vukčević, Miodrag, Bojović, Boško, Hadžievski, Ljupčo, Allsop, Thomas, Webb, D. J., "A long-period fibre grating sensor for respiratory monitoring" in PHOTONICA2015 : 5th International School and Conference on Photonics and COST actions: MP1204, BM1205 and MP1205 : book of abstracts; August 24-28, 2015; Belgrade (2015):168-168,
https://hdl.handle.net/21.15107/rcub_vinar_12011 .

TY  - JOUR
AU  - Vuković, Nikola
AU  - Daničić, Aleksandar
AU  - Radovanović, Jelena V.
AU  - Milanović, Vitomir B.
AU  - Indjin, Dragan
PY  - 2015
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/471
AB  - One of the challenges in the design of metamaterials unit cells is the reduction of losses caused by the metallic inclusions. In order to overcome this obstacle, it has been proposed to use the active medium as the unit cell. Quantum cascade lasers are great candidates for the active medium materials since they are able to provide high values of optical gain. In this paper we investigate and compare two quantum cascade structures optimized for emission frequencies lower than 2 THz and simulate the effect of a strong magnetic field applied perpendicularly to the layers. Comprehensive description of conduction-band nonparabolicity is used to calculate the electronic structure, and subsequently evaluate the longitudinal optical phonon and interface roughness scattering rates and solve the system of rate equations which govern the distribution of carriers among the Landau levels. Once we assess the degree of population inversion, we have all the necessary information about the permittivity component along the growth direction of the structure and may determine the conditions under which the structure displays negative refraction.
T2  - Optical and Quantum Electronics
T1  - Possibilities of achieving negative refraction in QCL-based semiconductor metamaterials in the THz spectral range
VL  - 47
IS  - 4
SP  - 883
EP  - 891
DO  - 10.1007/s11082-014-0020-2
ER  - 

@article{
author = "Vuković, Nikola and Daničić, Aleksandar and Radovanović, Jelena V. and Milanović, Vitomir B. and Indjin, Dragan",
year = "2015",
abstract = "One of the challenges in the design of metamaterials unit cells is the reduction of losses caused by the metallic inclusions. In order to overcome this obstacle, it has been proposed to use the active medium as the unit cell. Quantum cascade lasers are great candidates for the active medium materials since they are able to provide high values of optical gain. In this paper we investigate and compare two quantum cascade structures optimized for emission frequencies lower than 2 THz and simulate the effect of a strong magnetic field applied perpendicularly to the layers. Comprehensive description of conduction-band nonparabolicity is used to calculate the electronic structure, and subsequently evaluate the longitudinal optical phonon and interface roughness scattering rates and solve the system of rate equations which govern the distribution of carriers among the Landau levels. Once we assess the degree of population inversion, we have all the necessary information about the permittivity component along the growth direction of the structure and may determine the conditions under which the structure displays negative refraction.",
journal = "Optical and Quantum Electronics",
title = "Possibilities of achieving negative refraction in QCL-based semiconductor metamaterials in the THz spectral range",
volume = "47",
number = "4",
pages = "883-891",
doi = "10.1007/s11082-014-0020-2"
}

Vuković, N., Daničić, A., Radovanović, J. V., Milanović, V. B.,& Indjin, D.. (2015). Possibilities of achieving negative refraction in QCL-based semiconductor metamaterials in the THz spectral range. in Optical and Quantum Electronics, 47(4), 883-891.
https://doi.org/10.1007/s11082-014-0020-2

Vuković N, Daničić A, Radovanović JV, Milanović VB, Indjin D. Possibilities of achieving negative refraction in QCL-based semiconductor metamaterials in the THz spectral range. in Optical and Quantum Electronics. 2015;47(4):883-891.
doi:10.1007/s11082-014-0020-2 .

Vuković, Nikola, Daničić, Aleksandar, Radovanović, Jelena V., Milanović, Vitomir B., Indjin, Dragan, "Possibilities of achieving negative refraction in QCL-based semiconductor metamaterials in the THz spectral range" in Optical and Quantum Electronics, 47, no. 4 (2015):883-891,
https://doi.org/10.1007/s11082-014-0020-2 . .

TY  - CONF
AU  - Daničić, Aleksandar
AU  - Vuković, N.
AU  - Radovanović, J.
AU  - Milanović, V.
PY  - 2015
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/12002
AB  - The rapidly emerging field of nano-optoelectronics is based on the understanding and control of intersubband transitions in nano-dimensional systems. One of the most striking outcomes of intersubband transitions engineering is the quantum cascade laser (QCL) – an efficient and reliable unipolar semiconductor laser source [1], with the possibility to operate from the mid-infrared (MIR) to the THz range of frequencies. These powerful devices are particularly appreciated for such wide scope of operating wavelengths which can be achieved by using the same heterostructure combination, but changing the design of the active region, i.e. ‘tailoring’ the layers’ widths and composition. This renders QCLs suitable for numerous applications, including free-space communications, medical diagnostics and in particular, chemical sensing and monitoring [2]. In the MIR part of the spectrum, QCLs are of great interest for gas sensing and monitoring. We explore the possibilities of using advanced tools for global optimization, namely the genetic algorithm, to obtain structural parameters of gain-maximized QCL emitting at specified wavelengths, suitable for detection of pollutant gasses, such as SO2, HNO3, CH4 and NH3, in the ambient air. Then we introduce a strong external magnetic field perpendicular to the epitaxial layers, to fine tune the laser output properties [2]. This magnetic field alters the electron energy spectrum by splitting the continuous energy subbands into discrete Landau levels whose arrangement influences the magnitude of the optical gain. In addition, strong effects of band nonparabolicity result in subtle changes in the lasing wavelength at magnetic fields which maximize the gain, thus allowing us to explore the prospects of multi-wavelength emission of the given structure. THz frequencies belong to the quite under-utilized part of the electromagnetic spectrum, despite their significant application potential. This is mostly due to the lack of coherent solid-state THz sources. The so called „THz gap“ falls between two frequency ranges that have been well developed, the microwave and millimeter-wave frequency range. THz QCLs are great candidates to fill in this gap [3]. We have analyzed two structures lasing in this region (both of them reported in the literature, but not studied under the influence of an external magnetic field), the three- and four-well (per period) based structures that operate at 3.9THz and 1.9THz, respectively, implemented in GaAs/Al0.15Ga0.85As. Numerical results are presented for magnetic field values from 1.5 T up to 20 T, while the band nonparabolicity is carefully accounted for. Because of their high output gain, QCLs are suitable to be used as active media in metamaterial unit cells, thus enabling evasion of metallic inclusions present in conventional metamaterials [4]. We analyze a quantum cascade structure lasing at 4.6THz, placed under the influence of a strong magnetic field. We first solve the full system of rate equations for all the relevant Landau levels, and obtain the necessary information about the carrier distribution among the levels, after which we are able to evaluate the permittivity component along the growth direction of the structure, as well as the range of frequencies at which the structure exhibits negative refraction for a predefined total electron sheet density.
PB  - Belgrade : Vinča Institute of Nuclear Sciences
C3  - PHOTONICA2015 : 5th International School and Conference on Photonics and COST actions: MP1204, BM1205 and MP1205 : book of abstracts; August 24-28, 2015; Belgrade
T1  - Modeling and applications of Quantum Cascade in external magnetic field
SP  - 38
EP  - 39
UR  - https://hdl.handle.net/21.15107/rcub_vinar_12002
ER  - 

@conference{
author = "Daničić, Aleksandar and Vuković, N. and Radovanović, J. and Milanović, V.",
year = "2015",
abstract = "The rapidly emerging field of nano-optoelectronics is based on the understanding and control of intersubband transitions in nano-dimensional systems. One of the most striking outcomes of intersubband transitions engineering is the quantum cascade laser (QCL) – an efficient and reliable unipolar semiconductor laser source [1], with the possibility to operate from the mid-infrared (MIR) to the THz range of frequencies. These powerful devices are particularly appreciated for such wide scope of operating wavelengths which can be achieved by using the same heterostructure combination, but changing the design of the active region, i.e. ‘tailoring’ the layers’ widths and composition. This renders QCLs suitable for numerous applications, including free-space communications, medical diagnostics and in particular, chemical sensing and monitoring [2]. In the MIR part of the spectrum, QCLs are of great interest for gas sensing and monitoring. We explore the possibilities of using advanced tools for global optimization, namely the genetic algorithm, to obtain structural parameters of gain-maximized QCL emitting at specified wavelengths, suitable for detection of pollutant gasses, such as SO2, HNO3, CH4 and NH3, in the ambient air. Then we introduce a strong external magnetic field perpendicular to the epitaxial layers, to fine tune the laser output properties [2]. This magnetic field alters the electron energy spectrum by splitting the continuous energy subbands into discrete Landau levels whose arrangement influences the magnitude of the optical gain. In addition, strong effects of band nonparabolicity result in subtle changes in the lasing wavelength at magnetic fields which maximize the gain, thus allowing us to explore the prospects of multi-wavelength emission of the given structure. THz frequencies belong to the quite under-utilized part of the electromagnetic spectrum, despite their significant application potential. This is mostly due to the lack of coherent solid-state THz sources. The so called „THz gap“ falls between two frequency ranges that have been well developed, the microwave and millimeter-wave frequency range. THz QCLs are great candidates to fill in this gap [3]. We have analyzed two structures lasing in this region (both of them reported in the literature, but not studied under the influence of an external magnetic field), the three- and four-well (per period) based structures that operate at 3.9THz and 1.9THz, respectively, implemented in GaAs/Al0.15Ga0.85As. Numerical results are presented for magnetic field values from 1.5 T up to 20 T, while the band nonparabolicity is carefully accounted for. Because of their high output gain, QCLs are suitable to be used as active media in metamaterial unit cells, thus enabling evasion of metallic inclusions present in conventional metamaterials [4]. We analyze a quantum cascade structure lasing at 4.6THz, placed under the influence of a strong magnetic field. We first solve the full system of rate equations for all the relevant Landau levels, and obtain the necessary information about the carrier distribution among the levels, after which we are able to evaluate the permittivity component along the growth direction of the structure, as well as the range of frequencies at which the structure exhibits negative refraction for a predefined total electron sheet density.",
publisher = "Belgrade : Vinča Institute of Nuclear Sciences",
journal = "PHOTONICA2015 : 5th International School and Conference on Photonics and COST actions: MP1204, BM1205 and MP1205 : book of abstracts; August 24-28, 2015; Belgrade",
title = "Modeling and applications of Quantum Cascade in external magnetic field",
pages = "38-39",
url = "https://hdl.handle.net/21.15107/rcub_vinar_12002"
}

Daničić, A., Vuković, N., Radovanović, J.,& Milanović, V.. (2015). Modeling and applications of Quantum Cascade in external magnetic field. in PHOTONICA2015 : 5th International School and Conference on Photonics and COST actions: MP1204, BM1205 and MP1205 : book of abstracts; August 24-28, 2015; Belgrade
Belgrade : Vinča Institute of Nuclear Sciences., 38-39.
https://hdl.handle.net/21.15107/rcub_vinar_12002

Daničić A, Vuković N, Radovanović J, Milanović V. Modeling and applications of Quantum Cascade in external magnetic field. in PHOTONICA2015 : 5th International School and Conference on Photonics and COST actions: MP1204, BM1205 and MP1205 : book of abstracts; August 24-28, 2015; Belgrade. 2015;:38-39.
https://hdl.handle.net/21.15107/rcub_vinar_12002 .

Daničić, Aleksandar, Vuković, N., Radovanović, J., Milanović, V., "Modeling and applications of Quantum Cascade in external magnetic field" in PHOTONICA2015 : 5th International School and Conference on Photonics and COST actions: MP1204, BM1205 and MP1205 : book of abstracts; August 24-28, 2015; Belgrade (2015):38-39,
https://hdl.handle.net/21.15107/rcub_vinar_12002 .

TY  - JOUR
AU  - Radosavljević, Ana
AU  - Daničić, Aleksandar
AU  - Petrović, Jovana S.
AU  - Maluckov, Aleksandra
AU  - Hadžievski, Ljupčo
PY  - 2015
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/872
AB  - Multicore fibers with linearly coupled cores are considered as a means of the coherent transport needed for high-capacity communication systems and high-power fiber lasers. The conditions of the existence and stability of coherent light propagation in multicore fibers with circularly arranged cores are derived. The multicore fiber is modeled by the linear discrete complex Ginzburg-Landau equation, while its eigenvalues are found analytically. The inverse eigenvalue problem proposing the commensurability of eigenvalues is solved to find the intercore coupling coefficients that support periodic revivals of the input state. Both planar modes and vortices are considered. Effects of the central core and material loss/gain on eigenvalue commensurability conditions and mode dynamics are studied in detail. (C) 2015 Optical Society of America
T2  - Journal of the Optical Society of America. B: Optical Physics
T1  - Coherent light propagation through multicore optical fibers with linearly coupled cores
VL  - 32
IS  - 12
SP  - 2520
EP  - 2527
DO  - 10.1364/JOSAB.32.002520
ER  - 

@article{
author = "Radosavljević, Ana and Daničić, Aleksandar and Petrović, Jovana S. and Maluckov, Aleksandra and Hadžievski, Ljupčo",
year = "2015",
abstract = "Multicore fibers with linearly coupled cores are considered as a means of the coherent transport needed for high-capacity communication systems and high-power fiber lasers. The conditions of the existence and stability of coherent light propagation in multicore fibers with circularly arranged cores are derived. The multicore fiber is modeled by the linear discrete complex Ginzburg-Landau equation, while its eigenvalues are found analytically. The inverse eigenvalue problem proposing the commensurability of eigenvalues is solved to find the intercore coupling coefficients that support periodic revivals of the input state. Both planar modes and vortices are considered. Effects of the central core and material loss/gain on eigenvalue commensurability conditions and mode dynamics are studied in detail. (C) 2015 Optical Society of America",
journal = "Journal of the Optical Society of America. B: Optical Physics",
title = "Coherent light propagation through multicore optical fibers with linearly coupled cores",
volume = "32",
number = "12",
pages = "2520-2527",
doi = "10.1364/JOSAB.32.002520"
}

Radosavljević, A., Daničić, A., Petrović, J. S., Maluckov, A.,& Hadžievski, L.. (2015). Coherent light propagation through multicore optical fibers with linearly coupled cores. in Journal of the Optical Society of America. B: Optical Physics, 32(12), 2520-2527.
https://doi.org/10.1364/JOSAB.32.002520

Radosavljević A, Daničić A, Petrović JS, Maluckov A, Hadžievski L. Coherent light propagation through multicore optical fibers with linearly coupled cores. in Journal of the Optical Society of America. B: Optical Physics. 2015;32(12):2520-2527.
doi:10.1364/JOSAB.32.002520 .

Radosavljević, Ana, Daničić, Aleksandar, Petrović, Jovana S., Maluckov, Aleksandra, Hadžievski, Ljupčo, "Coherent light propagation through multicore optical fibers with linearly coupled cores" in Journal of the Optical Society of America. B: Optical Physics, 32, no. 12 (2015):2520-2527,
https://doi.org/10.1364/JOSAB.32.002520 . .

TY  - CONF
AU  - Vuković, Nikola
AU  - Daničić, Aleksandar
AU  - Radovanović, Jelena
AU  - Milanović, Vitomir
AU  - Boiko, D. L.
PY  - 2015
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/10956
AB  - Quantum Cascade Lasers (QCLs) producing picosecond pulses of high peak power will find numerous novel applications for time-resolved MIR spectroscopy, free space communication, remote atmosphere sensing etc. The short upper state lifetime (~1 ps) in QCLs prohibits passive mode-locking or Q-switched operation because the gain recovers much faster than the pulse repetition rate. Gain switched pulse production has been attempted yielding 120 ps pulse width [1] and active mode-locking was achieved in QCL utilizing diagonal transition [2]. Unfortunately, diagonal transition rendered QCL operation temperature out of the practical use. Experiments reported in [3] evidence that some QCL structures exhibit features of multimode Risken-Nummedal-Graham-Haken (RNGH) instabilities [4,5] at low excess above lasing threshold (pth2<1.1). The onset of such RNGH instabilities and excitation of regular self-pulsations may provide practical means to produce picosecond pulses in the MIR spectral range. Conventional RNGH analysis [4,5] predicts that the second threshold pth2 is in the range of 9 to 16 times above lasing threshold, does not take the spatial grating of population inversion into account and barely agrees with experiments in unidirectional ring fiber lasers [6]. Here we consider Fabry-Perot (FP) cavity QCLs and conventional semiconductor quantum well (QW) LDs. Like in reference [3], we take into account the effect of the induced grating of population inversion, but we also incorporate the grating of the medium polarization and its relaxation due to carrier diffusion. This allows us to explain low second threshold in QCLs without inducing the ambiguous assumption of Ref. [3] of a built-in saturable absorber and Kerr lensing-effect in the waveguide of QCL. We further elucidate the importance of unipolar diffusion in QCLs and ambipolar diffusion in conventional LDs: without diffusion, the second threshold would be too low and independent of the lasing wavelength. Time domain simulations utilizing travelling wave rate equation model of Ref. [7] show irregular self-pulsations, in agreement with experiment in [3]. Shortening of the cavity length down to L=100μm results in the increase of the second threshold up to 2.3-2.5. Above RNGH threshold, steady state regular self-pulsations can be established, preceded by a high-amplitude burst, which might be attributed to Dicke superradiance (SR) [8]. Very high pth2 in conventional LDs is predicted by the model, attributed to ambipolar diffusion. Just like QCLs above the RNGH threshold, FP cavity LDs would exhibit SR emission burst followed by regular RNGH self-pulsations.
PB  - Belgrade : Vinča Institute of Nuclear Sciences
C3  - PHOTONICA2015 : 5th International School and Conference on Photonics and COST actions: MP1204, BM1205 and MP1205 : book of abstracts; August 24-28, 2015; Belgrade
T1  - Multimode RNGH instabilities of Fabry-Perot cavity QCLs: Impact of diffusion
SP  - 115
EP  - 116
UR  - https://hdl.handle.net/21.15107/rcub_vinar_10956
ER  - 

@conference{
author = "Vuković, Nikola and Daničić, Aleksandar and Radovanović, Jelena and Milanović, Vitomir and Boiko, D. L.",
year = "2015",
abstract = "Quantum Cascade Lasers (QCLs) producing picosecond pulses of high peak power will find numerous novel applications for time-resolved MIR spectroscopy, free space communication, remote atmosphere sensing etc. The short upper state lifetime (~1 ps) in QCLs prohibits passive mode-locking or Q-switched operation because the gain recovers much faster than the pulse repetition rate. Gain switched pulse production has been attempted yielding 120 ps pulse width [1] and active mode-locking was achieved in QCL utilizing diagonal transition [2]. Unfortunately, diagonal transition rendered QCL operation temperature out of the practical use. Experiments reported in [3] evidence that some QCL structures exhibit features of multimode Risken-Nummedal-Graham-Haken (RNGH) instabilities [4,5] at low excess above lasing threshold (pth2<1.1). The onset of such RNGH instabilities and excitation of regular self-pulsations may provide practical means to produce picosecond pulses in the MIR spectral range. Conventional RNGH analysis [4,5] predicts that the second threshold pth2 is in the range of 9 to 16 times above lasing threshold, does not take the spatial grating of population inversion into account and barely agrees with experiments in unidirectional ring fiber lasers [6]. Here we consider Fabry-Perot (FP) cavity QCLs and conventional semiconductor quantum well (QW) LDs. Like in reference [3], we take into account the effect of the induced grating of population inversion, but we also incorporate the grating of the medium polarization and its relaxation due to carrier diffusion. This allows us to explain low second threshold in QCLs without inducing the ambiguous assumption of Ref. [3] of a built-in saturable absorber and Kerr lensing-effect in the waveguide of QCL. We further elucidate the importance of unipolar diffusion in QCLs and ambipolar diffusion in conventional LDs: without diffusion, the second threshold would be too low and independent of the lasing wavelength. Time domain simulations utilizing travelling wave rate equation model of Ref. [7] show irregular self-pulsations, in agreement with experiment in [3]. Shortening of the cavity length down to L=100μm results in the increase of the second threshold up to 2.3-2.5. Above RNGH threshold, steady state regular self-pulsations can be established, preceded by a high-amplitude burst, which might be attributed to Dicke superradiance (SR) [8]. Very high pth2 in conventional LDs is predicted by the model, attributed to ambipolar diffusion. Just like QCLs above the RNGH threshold, FP cavity LDs would exhibit SR emission burst followed by regular RNGH self-pulsations.",
publisher = "Belgrade : Vinča Institute of Nuclear Sciences",
journal = "PHOTONICA2015 : 5th International School and Conference on Photonics and COST actions: MP1204, BM1205 and MP1205 : book of abstracts; August 24-28, 2015; Belgrade",
title = "Multimode RNGH instabilities of Fabry-Perot cavity QCLs: Impact of diffusion",
pages = "115-116",
url = "https://hdl.handle.net/21.15107/rcub_vinar_10956"
}

Vuković, N., Daničić, A., Radovanović, J., Milanović, V.,& Boiko, D. L.. (2015). Multimode RNGH instabilities of Fabry-Perot cavity QCLs: Impact of diffusion. in PHOTONICA2015 : 5th International School and Conference on Photonics and COST actions: MP1204, BM1205 and MP1205 : book of abstracts; August 24-28, 2015; Belgrade
Belgrade : Vinča Institute of Nuclear Sciences., 115-116.
https://hdl.handle.net/21.15107/rcub_vinar_10956

Vuković N, Daničić A, Radovanović J, Milanović V, Boiko DL. Multimode RNGH instabilities of Fabry-Perot cavity QCLs: Impact of diffusion. in PHOTONICA2015 : 5th International School and Conference on Photonics and COST actions: MP1204, BM1205 and MP1205 : book of abstracts; August 24-28, 2015; Belgrade. 2015;:115-116.
https://hdl.handle.net/21.15107/rcub_vinar_10956 .

Vuković, Nikola, Daničić, Aleksandar, Radovanović, Jelena, Milanović, Vitomir, Boiko, D. L., "Multimode RNGH instabilities of Fabry-Perot cavity QCLs: Impact of diffusion" in PHOTONICA2015 : 5th International School and Conference on Photonics and COST actions: MP1204, BM1205 and MP1205 : book of abstracts; August 24-28, 2015; Belgrade (2015):115-116,
https://hdl.handle.net/21.15107/rcub_vinar_10956 .

TY  - JOUR
AU  - Petrovic, M. D.
AU  - Petrović, Jovana S.
AU  - Daničić, Aleksandar
AU  - Vukcevic, M.
AU  - Bojović, Boško
AU  - Hadžievski, Ljupčo
AU  - Allsop, Thomas P.
AU  - Lloyd, G.
AU  - Webb, David J.
PY  - 2014
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/5946
AB  - In non-invasive ventilation, continuous monitoring of respiratory volumes is essential. Here, we present a method for the measurement of respiratory volumes by a single fiber-grating sensor of bending and provide the proof-of-principle by applying a calibration-test measurement procedure on a set of 18 healthy volunteers. Results establish a linear correlation between a change in lung volume and the corresponding change in a local thorax curvature. They also show good sensor accuracy in measurements of tidal and minute respiratory volumes for different types of breathing. The proposed technique does not rely on the air flow through an oronasal mask or the observation of chest movement by a clinician, which distinguishes it from the current clinical practice. (C) 2014 Optical Society of America
T2  - Biomedical Optics Express
T1  - Non-invasive respiratory monitoring using long-period fiber grating sensors
VL  - 5
IS  - 4
SP  - 1136
EP  - 1144
DO  - 10.1364/BOE.5.001136
ER  - 

@article{
author = "Petrovic, M. D. and Petrović, Jovana S. and Daničić, Aleksandar and Vukcevic, M. and Bojović, Boško and Hadžievski, Ljupčo and Allsop, Thomas P. and Lloyd, G. and Webb, David J.",
year = "2014",
abstract = "In non-invasive ventilation, continuous monitoring of respiratory volumes is essential. Here, we present a method for the measurement of respiratory volumes by a single fiber-grating sensor of bending and provide the proof-of-principle by applying a calibration-test measurement procedure on a set of 18 healthy volunteers. Results establish a linear correlation between a change in lung volume and the corresponding change in a local thorax curvature. They also show good sensor accuracy in measurements of tidal and minute respiratory volumes for different types of breathing. The proposed technique does not rely on the air flow through an oronasal mask or the observation of chest movement by a clinician, which distinguishes it from the current clinical practice. (C) 2014 Optical Society of America",
journal = "Biomedical Optics Express",
title = "Non-invasive respiratory monitoring using long-period fiber grating sensors",
volume = "5",
number = "4",
pages = "1136-1144",
doi = "10.1364/BOE.5.001136"
}

Petrovic, M. D., Petrović, J. S., Daničić, A., Vukcevic, M., Bojović, B., Hadžievski, L., Allsop, T. P., Lloyd, G.,& Webb, D. J.. (2014). Non-invasive respiratory monitoring using long-period fiber grating sensors. in Biomedical Optics Express, 5(4), 1136-1144.
https://doi.org/10.1364/BOE.5.001136

Petrovic MD, Petrović JS, Daničić A, Vukcevic M, Bojović B, Hadžievski L, Allsop TP, Lloyd G, Webb DJ. Non-invasive respiratory monitoring using long-period fiber grating sensors. in Biomedical Optics Express. 2014;5(4):1136-1144.
doi:10.1364/BOE.5.001136 .

Petrovic, M. D., Petrović, Jovana S., Daničić, Aleksandar, Vukcevic, M., Bojović, Boško, Hadžievski, Ljupčo, Allsop, Thomas P., Lloyd, G., Webb, David J., "Non-invasive respiratory monitoring using long-period fiber grating sensors" in Biomedical Optics Express, 5, no. 4 (2014):1136-1144,
https://doi.org/10.1364/BOE.5.001136 . .

TY  - JOUR
AU  - Petrović, Marija D.
AU  - Daničić, Aleksandar
AU  - Atanasoski, Vladimir
AU  - Radosavljevic, S.
AU  - Prodanovic, V.
AU  - Miljković, Nadica
AU  - Petrović, Jovana S.
AU  - Petrovic, D.
AU  - Bojović, Boško
AU  - Hadžievski, Ljupčo
AU  - Allsop, Thomas P.
AU  - Lloyd, G.
AU  - Webb, David J.
PY  - 2013
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/7019
AB  - Mechanical physiological pulsations are movements of a body surface incited by the movements of muscles in organs inside the body. Here we demonstrate the use of long-period grating sensors in the detection of cardio-vascular pulsations (CVP), in particular apex and carotid pulsations. To calibrate the sensors, we use a mechanical tool designed specifically to measure the sensor response to a localized perturbation at different grating curvatures as working points. From the data we infer the amplitude of the CVP. Together with the electrophysiological signals, the CVP signals obtained from the sensors can provide significant information on heart function which is inaccessible to the electrocardiogram. The low cost and easy handling of the fibre sensors increase their prospects to become the sensors of choice for novel diagnostic devices.
T2  - Physica Scripta
T1  - Fibre-grating sensors for the measurement of physiological pulsations
VL  - T157
SP  - 014022
DO  - 10.1088/0031-8949/2013/T157/014022
ER  - 

@article{
author = "Petrović, Marija D. and Daničić, Aleksandar and Atanasoski, Vladimir and Radosavljevic, S. and Prodanovic, V. and Miljković, Nadica and Petrović, Jovana S. and Petrovic, D. and Bojović, Boško and Hadžievski, Ljupčo and Allsop, Thomas P. and Lloyd, G. and Webb, David J.",
year = "2013",
abstract = "Mechanical physiological pulsations are movements of a body surface incited by the movements of muscles in organs inside the body. Here we demonstrate the use of long-period grating sensors in the detection of cardio-vascular pulsations (CVP), in particular apex and carotid pulsations. To calibrate the sensors, we use a mechanical tool designed specifically to measure the sensor response to a localized perturbation at different grating curvatures as working points. From the data we infer the amplitude of the CVP. Together with the electrophysiological signals, the CVP signals obtained from the sensors can provide significant information on heart function which is inaccessible to the electrocardiogram. The low cost and easy handling of the fibre sensors increase their prospects to become the sensors of choice for novel diagnostic devices.",
journal = "Physica Scripta",
title = "Fibre-grating sensors for the measurement of physiological pulsations",
volume = "T157",
pages = "014022",
doi = "10.1088/0031-8949/2013/T157/014022"
}

Petrović, M. D., Daničić, A., Atanasoski, V., Radosavljevic, S., Prodanovic, V., Miljković, N., Petrović, J. S., Petrovic, D., Bojović, B., Hadžievski, L., Allsop, T. P., Lloyd, G.,& Webb, D. J.. (2013). Fibre-grating sensors for the measurement of physiological pulsations. in Physica Scripta, T157, 014022.
https://doi.org/10.1088/0031-8949/2013/T157/014022

Petrović MD, Daničić A, Atanasoski V, Radosavljevic S, Prodanovic V, Miljković N, Petrović JS, Petrovic D, Bojović B, Hadžievski L, Allsop TP, Lloyd G, Webb DJ. Fibre-grating sensors for the measurement of physiological pulsations. in Physica Scripta. 2013;T157:014022.
doi:10.1088/0031-8949/2013/T157/014022 .

Petrović, Marija D., Daničić, Aleksandar, Atanasoski, Vladimir, Radosavljevic, S., Prodanovic, V., Miljković, Nadica, Petrović, Jovana S., Petrovic, D., Bojović, Boško, Hadžievski, Ljupčo, Allsop, Thomas P., Lloyd, G., Webb, David J., "Fibre-grating sensors for the measurement of physiological pulsations" in Physica Scripta, T157 (2013):014022,
https://doi.org/10.1088/0031-8949/2013/T157/014022 . .

TY  - CONF
AU  - Petrovic, Marija
AU  - Petrović, Jovana S.
AU  - Simic, Goran
AU  - Ilic, Igor
AU  - Daničić, Aleksandar
AU  - Vukcevic, Miodrag
AU  - Bojović, Boško
AU  - Hadžievski, Ljupčo
AU  - Allsop, Thomas P.
AU  - Webb, David J.
PY  - 2013
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/7036
AB  - Respiratory-volume monitoring is an indispensable part of mechanical ventilation. Here we present a new method of the respiratory-volume measurement based on a single fibre-optical long-period sensor of bending and the correlation between torso curvature and lung volume. Unlike the commonly used air-flow based measurement methods the proposed sensor is drift-free and immune to air-leaks. In the paper, we explain the working principle of sensors, a two-step calibration-test measurement procedure and present results that establish a linear correlation between the change in the local thorax curvature and the change of the lung volume. We also discuss the advantages and limitations of these sensors with respect to the current standards.
T1  - A New Method for Respiratory-Volume Monitoring Based on Long-Period Fibre Gratings
SP  - 2660
EP  - 2663
UR  - https://hdl.handle.net/21.15107/rcub_vinar_7036
ER  - 

@conference{
author = "Petrovic, Marija and Petrović, Jovana S. and Simic, Goran and Ilic, Igor and Daničić, Aleksandar and Vukcevic, Miodrag and Bojović, Boško and Hadžievski, Ljupčo and Allsop, Thomas P. and Webb, David J.",
year = "2013",
abstract = "Respiratory-volume monitoring is an indispensable part of mechanical ventilation. Here we present a new method of the respiratory-volume measurement based on a single fibre-optical long-period sensor of bending and the correlation between torso curvature and lung volume. Unlike the commonly used air-flow based measurement methods the proposed sensor is drift-free and immune to air-leaks. In the paper, we explain the working principle of sensors, a two-step calibration-test measurement procedure and present results that establish a linear correlation between the change in the local thorax curvature and the change of the lung volume. We also discuss the advantages and limitations of these sensors with respect to the current standards.",
title = "A New Method for Respiratory-Volume Monitoring Based on Long-Period Fibre Gratings",
pages = "2660-2663",
url = "https://hdl.handle.net/21.15107/rcub_vinar_7036"
}

Petrovic, M., Petrović, J. S., Simic, G., Ilic, I., Daničić, A., Vukcevic, M., Bojović, B., Hadžievski, L., Allsop, T. P.,& Webb, D. J.. (2013). A New Method for Respiratory-Volume Monitoring Based on Long-Period Fibre Gratings. , 2660-2663.
https://hdl.handle.net/21.15107/rcub_vinar_7036

Petrovic M, Petrović JS, Simic G, Ilic I, Daničić A, Vukcevic M, Bojović B, Hadžievski L, Allsop TP, Webb DJ. A New Method for Respiratory-Volume Monitoring Based on Long-Period Fibre Gratings. 2013;:2660-2663.
https://hdl.handle.net/21.15107/rcub_vinar_7036 .

Petrovic, Marija, Petrović, Jovana S., Simic, Goran, Ilic, Igor, Daničić, Aleksandar, Vukcevic, Miodrag, Bojović, Boško, Hadžievski, Ljupčo, Allsop, Thomas P., Webb, David J., "A New Method for Respiratory-Volume Monitoring Based on Long-Period Fibre Gratings" (2013):2660-2663,
https://hdl.handle.net/21.15107/rcub_vinar_7036 .

TY  - CONF
AU  - Vukcevic, Miodrag
AU  - Bojović, Boško
AU  - Petrović, Marija
AU  - Simic, Goran
AU  - Daničić, Aleksandar
AU  - Petrović, Jovana S.
AU  - Hadžievski, Ljupčo
PY  - 2013
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/2740
C3  - European Respiratory Journal
T1  - An early non-invasive detection of the patient inspiratory effort for patient-ventilator synchronization
VL  - 42
UR  - https://hdl.handle.net/21.15107/rcub_vinar_2740
ER  - 

@conference{
author = "Vukcevic, Miodrag and Bojović, Boško and Petrović, Marija and Simic, Goran and Daničić, Aleksandar and Petrović, Jovana S. and Hadžievski, Ljupčo",
year = "2013",
journal = "European Respiratory Journal",
title = "An early non-invasive detection of the patient inspiratory effort for patient-ventilator synchronization",
volume = "42",
url = "https://hdl.handle.net/21.15107/rcub_vinar_2740"
}

Vukcevic, M., Bojović, B., Petrović, M., Simic, G., Daničić, A., Petrović, J. S.,& Hadžievski, L.. (2013). An early non-invasive detection of the patient inspiratory effort for patient-ventilator synchronization. in European Respiratory Journal, 42.
https://hdl.handle.net/21.15107/rcub_vinar_2740

Vukcevic M, Bojović B, Petrović M, Simic G, Daničić A, Petrović JS, Hadžievski L. An early non-invasive detection of the patient inspiratory effort for patient-ventilator synchronization. in European Respiratory Journal. 2013;42.
https://hdl.handle.net/21.15107/rcub_vinar_2740 .

Vukcevic, Miodrag, Bojović, Boško, Petrović, Marija, Simic, Goran, Daničić, Aleksandar, Petrović, Jovana S., Hadžievski, Ljupčo, "An early non-invasive detection of the patient inspiratory effort for patient-ventilator synchronization" in European Respiratory Journal, 42 (2013),
https://hdl.handle.net/21.15107/rcub_vinar_2740 .

TY  - CONF
AU  - Vukcevic, Miodrag
AU  - Bojović, Boško
AU  - Petrović, Marija
AU  - Petrović, Jovana S.
AU  - Daničić, Aleksandar
AU  - Simic, Goran
AU  - Hadžievski, Ljupčo
PY  - 2013
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/2741
C3  - European Respiratory Journal
T1  - A non-invasive LPG (long-period grating) fiber-optic sensing method for respiratory volume monitoring
VL  - 42
UR  - https://hdl.handle.net/21.15107/rcub_vinar_2741
ER  - 

@conference{
author = "Vukcevic, Miodrag and Bojović, Boško and Petrović, Marija and Petrović, Jovana S. and Daničić, Aleksandar and Simic, Goran and Hadžievski, Ljupčo",
year = "2013",
journal = "European Respiratory Journal",
title = "A non-invasive LPG (long-period grating) fiber-optic sensing method for respiratory volume monitoring",
volume = "42",
url = "https://hdl.handle.net/21.15107/rcub_vinar_2741"
}

Vukcevic, M., Bojović, B., Petrović, M., Petrović, J. S., Daničić, A., Simic, G.,& Hadžievski, L.. (2013). A non-invasive LPG (long-period grating) fiber-optic sensing method for respiratory volume monitoring. in European Respiratory Journal, 42.
https://hdl.handle.net/21.15107/rcub_vinar_2741

Vukcevic M, Bojović B, Petrović M, Petrović JS, Daničić A, Simic G, Hadžievski L. A non-invasive LPG (long-period grating) fiber-optic sensing method for respiratory volume monitoring. in European Respiratory Journal. 2013;42.
https://hdl.handle.net/21.15107/rcub_vinar_2741 .

Vukcevic, Miodrag, Bojović, Boško, Petrović, Marija, Petrović, Jovana S., Daničić, Aleksandar, Simic, Goran, Hadžievski, Ljupčo, "A non-invasive LPG (long-period grating) fiber-optic sensing method for respiratory volume monitoring" in European Respiratory Journal, 42 (2013),
https://hdl.handle.net/21.15107/rcub_vinar_2741 .

TY  - JOUR
AU  - Radovanović, Jelena V.
AU  - Ramović, Sabina
AU  - Daničić, Aleksandar
AU  - Milanović, Vitomir B.
PY  - 2012
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/5171
AB  - We have considered the realization of metamaterials based on semiconductor quantum nanostructures, in particular, with the structural arrangement as in quantum cascade laser (QCL) designed to achieve optical gain in the mid-infrared and terahertz part of the spectrum. The entire structure is placed in a strong external magnetic field, which facilitates the attainment of sufficient population inversion, necessary to manipulate the permittivity, and enable a left-handed regime.
T2  - Applied Physics. A: Materials Science and Processing
T1  - Negative refraction in semiconductor metamaterials based on quantum cascade laser design for the mid-IR and THz spectral range
VL  - 109
IS  - 4
SP  - 763
EP  - 768
DO  - 10.1007/s00339-012-7343-2
ER  - 

@article{
author = "Radovanović, Jelena V. and Ramović, Sabina and Daničić, Aleksandar and Milanović, Vitomir B.",
year = "2012",
abstract = "We have considered the realization of metamaterials based on semiconductor quantum nanostructures, in particular, with the structural arrangement as in quantum cascade laser (QCL) designed to achieve optical gain in the mid-infrared and terahertz part of the spectrum. The entire structure is placed in a strong external magnetic field, which facilitates the attainment of sufficient population inversion, necessary to manipulate the permittivity, and enable a left-handed regime.",
journal = "Applied Physics. A: Materials Science and Processing",
title = "Negative refraction in semiconductor metamaterials based on quantum cascade laser design for the mid-IR and THz spectral range",
volume = "109",
number = "4",
pages = "763-768",
doi = "10.1007/s00339-012-7343-2"
}

Radovanović, J. V., Ramović, S., Daničić, A.,& Milanović, V. B.. (2012). Negative refraction in semiconductor metamaterials based on quantum cascade laser design for the mid-IR and THz spectral range. in Applied Physics. A: Materials Science and Processing, 109(4), 763-768.
https://doi.org/10.1007/s00339-012-7343-2

Radovanović JV, Ramović S, Daničić A, Milanović VB. Negative refraction in semiconductor metamaterials based on quantum cascade laser design for the mid-IR and THz spectral range. in Applied Physics. A: Materials Science and Processing. 2012;109(4):763-768.
doi:10.1007/s00339-012-7343-2 .

Radovanović, Jelena V., Ramović, Sabina, Daničić, Aleksandar, Milanović, Vitomir B., "Negative refraction in semiconductor metamaterials based on quantum cascade laser design for the mid-IR and THz spectral range" in Applied Physics. A: Materials Science and Processing, 109, no. 4 (2012):763-768,
https://doi.org/10.1007/s00339-012-7343-2 . .

TY  - JOUR
AU  - Daničić, Aleksandar
AU  - Radovanović, Jelena V.
AU  - Indjin, Dragan
AU  - Ikonić, Zoran
PY  - 2012
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/6949
AB  - We present a detailed model for calculating the optical gain of a quantum cascade laser (QCL) that operates in the terahertz spectral range, when subjected to a strong magnetic field, as well as the total relaxation rates due to the emission of longitudinal-optical phonons and interface roughness scattering, as a function of the applied field. When the magnetic field is applied in the direction perpendicular to the plane of the layers, each energy state is split into a series of discrete Landau levels, which are magnetically tunable, and it is therefore possible to control the modulation of the population inversion and consequently the optical gain just by varying the magnetic field. In this model, the gain is obtained by solving the full system of rate equations, from which one can calculate the carrier density of each level. The simulations are performed on a system that comprises a two-well design QCL that operates at 4.6 THz, implemented in GaAs/Al0.15Ga0.85As. Numerical results are presented for magnetic field values from 1.5 T up to 20 T, while the band non-parabolicity is taken into account.
T2  - Physica Scripta
T1  - Modeling of electron relaxation processes and the optical gain in a magnetic-field assisted THz quantum cascade laser
VL  - T149
DO  - 10.1088/0031-8949/2012/T149/014017
ER  - 

@article{
author = "Daničić, Aleksandar and Radovanović, Jelena V. and Indjin, Dragan and Ikonić, Zoran",
year = "2012",
abstract = "We present a detailed model for calculating the optical gain of a quantum cascade laser (QCL) that operates in the terahertz spectral range, when subjected to a strong magnetic field, as well as the total relaxation rates due to the emission of longitudinal-optical phonons and interface roughness scattering, as a function of the applied field. When the magnetic field is applied in the direction perpendicular to the plane of the layers, each energy state is split into a series of discrete Landau levels, which are magnetically tunable, and it is therefore possible to control the modulation of the population inversion and consequently the optical gain just by varying the magnetic field. In this model, the gain is obtained by solving the full system of rate equations, from which one can calculate the carrier density of each level. The simulations are performed on a system that comprises a two-well design QCL that operates at 4.6 THz, implemented in GaAs/Al0.15Ga0.85As. Numerical results are presented for magnetic field values from 1.5 T up to 20 T, while the band non-parabolicity is taken into account.",
journal = "Physica Scripta",
title = "Modeling of electron relaxation processes and the optical gain in a magnetic-field assisted THz quantum cascade laser",
volume = "T149",
doi = "10.1088/0031-8949/2012/T149/014017"
}

Daničić, A., Radovanović, J. V., Indjin, D.,& Ikonić, Z.. (2012). Modeling of electron relaxation processes and the optical gain in a magnetic-field assisted THz quantum cascade laser. in Physica Scripta, T149.
https://doi.org/10.1088/0031-8949/2012/T149/014017

Daničić A, Radovanović JV, Indjin D, Ikonić Z. Modeling of electron relaxation processes and the optical gain in a magnetic-field assisted THz quantum cascade laser. in Physica Scripta. 2012;T149.
doi:10.1088/0031-8949/2012/T149/014017 .

Daničić, Aleksandar, Radovanović, Jelena V., Indjin, Dragan, Ikonić, Zoran, "Modeling of electron relaxation processes and the optical gain in a magnetic-field assisted THz quantum cascade laser" in Physica Scripta, T149 (2012),
https://doi.org/10.1088/0031-8949/2012/T149/014017 . .

TY  - CONF
AU  - Daničić, Aleksandar
AU  - Radovanović, Jelena V.
AU  - Milanović, V.
AU  - Inđin, Dragan
AU  - Ikonić, Zoran
PY  - 2011
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/10978
PB  - Belgrade : Vinča Institute of Nuclear Sciences
C3  - PHOTONICA2011 : 3rd International School and Conference on Photonics : book of abstracts; August 29- September 2, 2011; Belgrade
T1  - Modeling of electron relaxation processes and the optical gain in a magnet-field assisted THz quantum cascade laser
SP  - 115
EP  - 116
UR  - https://hdl.handle.net/21.15107/rcub_vinar_10978
ER  - 

@conference{
author = "Daničić, Aleksandar and Radovanović, Jelena V. and Milanović, V. and Inđin, Dragan and Ikonić, Zoran",
year = "2011",
publisher = "Belgrade : Vinča Institute of Nuclear Sciences",
journal = "PHOTONICA2011 : 3rd International School and Conference on Photonics : book of abstracts; August 29- September 2, 2011; Belgrade",
title = "Modeling of electron relaxation processes and the optical gain in a magnet-field assisted THz quantum cascade laser",
pages = "115-116",
url = "https://hdl.handle.net/21.15107/rcub_vinar_10978"
}

Daničić, A., Radovanović, J. V., Milanović, V., Inđin, D.,& Ikonić, Z.. (2011). Modeling of electron relaxation processes and the optical gain in a magnet-field assisted THz quantum cascade laser. in PHOTONICA2011 : 3rd International School and Conference on Photonics : book of abstracts; August 29- September 2, 2011; Belgrade
Belgrade : Vinča Institute of Nuclear Sciences., 115-116.
https://hdl.handle.net/21.15107/rcub_vinar_10978

Daničić A, Radovanović JV, Milanović V, Inđin D, Ikonić Z. Modeling of electron relaxation processes and the optical gain in a magnet-field assisted THz quantum cascade laser. in PHOTONICA2011 : 3rd International School and Conference on Photonics : book of abstracts; August 29- September 2, 2011; Belgrade. 2011;:115-116.
https://hdl.handle.net/21.15107/rcub_vinar_10978 .

Daničić, Aleksandar, Radovanović, Jelena V., Milanović, V., Inđin, Dragan, Ikonić, Zoran, "Modeling of electron relaxation processes and the optical gain in a magnet-field assisted THz quantum cascade laser" in PHOTONICA2011 : 3rd International School and Conference on Photonics : book of abstracts; August 29- September 2, 2011; Belgrade (2011):115-116,
https://hdl.handle.net/21.15107/rcub_vinar_10978 .

TY  - JOUR
AU  - Moro, Slaven
AU  - Daničić, Aleksandar
AU  - Alic, Nikola
AU  - Usechak, Nicholas G.
AU  - Radić, Stojan
PY  - 2011
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/4308
AB  - An all-fiber, tunable, short-wave infrared transmitter is demonstrated using efficient four-wave mixing in conventional L and O bands. To realize this source a highly-nonlinear fiber, exhibiting low bend loss over the short-wave infrared spectral band, is employed because of its advantageous properties as a nonlinear mixing medium. The transmitter was subsequently exploited to probe and detect trace levels of carbon dioxide in the 2051-nm spectral region where its beam properties, tunability, narrow linewidth, and stability all coalesce to permit this application. This work indicates this transmitter can serve as a robust source for sensing carbon dioxide and other trace gasses in the short-wave infrared spectral region and should therefore play an important role in future applications. (C) 2011 Optical Society of America
T2  - Optics Express
T1  - Widely-tunable parametric short-wave infrared transmitter for CO2 trace detection
VL  - 19
IS  - 9
SP  - 8173
EP  - 8178
DO  - 10.1364/OE.19.008173
ER  - 

@article{
author = "Moro, Slaven and Daničić, Aleksandar and Alic, Nikola and Usechak, Nicholas G. and Radić, Stojan",
year = "2011",
abstract = "An all-fiber, tunable, short-wave infrared transmitter is demonstrated using efficient four-wave mixing in conventional L and O bands. To realize this source a highly-nonlinear fiber, exhibiting low bend loss over the short-wave infrared spectral band, is employed because of its advantageous properties as a nonlinear mixing medium. The transmitter was subsequently exploited to probe and detect trace levels of carbon dioxide in the 2051-nm spectral region where its beam properties, tunability, narrow linewidth, and stability all coalesce to permit this application. This work indicates this transmitter can serve as a robust source for sensing carbon dioxide and other trace gasses in the short-wave infrared spectral region and should therefore play an important role in future applications. (C) 2011 Optical Society of America",
journal = "Optics Express",
title = "Widely-tunable parametric short-wave infrared transmitter for CO2 trace detection",
volume = "19",
number = "9",
pages = "8173-8178",
doi = "10.1364/OE.19.008173"
}

Moro, S., Daničić, A., Alic, N., Usechak, N. G.,& Radić, S.. (2011). Widely-tunable parametric short-wave infrared transmitter for CO2 trace detection. in Optics Express, 19(9), 8173-8178.
https://doi.org/10.1364/OE.19.008173

Moro S, Daničić A, Alic N, Usechak NG, Radić S. Widely-tunable parametric short-wave infrared transmitter for CO2 trace detection. in Optics Express. 2011;19(9):8173-8178.
doi:10.1364/OE.19.008173 .

Moro, Slaven, Daničić, Aleksandar, Alic, Nikola, Usechak, Nicholas G., Radić, Stojan, "Widely-tunable parametric short-wave infrared transmitter for CO2 trace detection" in Optics Express, 19, no. 9 (2011):8173-8178,
https://doi.org/10.1364/OE.19.008173 . .

TY  - JOUR
AU  - Daničić, Aleksandar
AU  - Radovanović, Jelena V.
AU  - Milanović, Vitomir B.
AU  - Indjin, Dragan
AU  - Ikonić, Zoran
PY  - 2010
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/3874
AB  - We explore the possibilities of using advanced tools for global optimization, namely the genetic algorithm, to obtain structural parameters of gain-maximized quantum cascade laser (QCL) emitting at specified wavelengths, suitable for detection of pollutant gasses, such as SO(2), HNO(3), CH(4) and NH(3), in the ambient air. Upon completing this initial optimization stage, we introduce a strong external magnetic field perpendicular to the epitaxial layers, to fine tune the laser output properties. This magnetic field alters the electron energy spectrum by splitting the continuous energy subbands into discrete Landau levels whose arrangement influences the magnitude of the optical gain. In addition, strong effects of band nonparabolicity result in subtle changes in the lasing wavelength at magnetic fields which maximize the gain, thus allowing us to explore the prospects of multi-wavelength emission of the given structure, and achieving resonance with additional compounds, absorbing at wavelengths close to the original one. Numerical results are presented for GaAs/Al(x)Ga(1-x) As based QCL structures designed for operation in the mid-infrared part of the spectrum.
T2  - Journal of Physics. D: Applied Physics
T1  - Optimization and magnetic-field tunability of quantum cascade laser for applications in trace gas detection and monitoring
VL  - 43
IS  - 4
DO  - 10.1088/0022-3727/43/4/045101
ER  - 

@article{
author = "Daničić, Aleksandar and Radovanović, Jelena V. and Milanović, Vitomir B. and Indjin, Dragan and Ikonić, Zoran",
year = "2010",
abstract = "We explore the possibilities of using advanced tools for global optimization, namely the genetic algorithm, to obtain structural parameters of gain-maximized quantum cascade laser (QCL) emitting at specified wavelengths, suitable for detection of pollutant gasses, such as SO(2), HNO(3), CH(4) and NH(3), in the ambient air. Upon completing this initial optimization stage, we introduce a strong external magnetic field perpendicular to the epitaxial layers, to fine tune the laser output properties. This magnetic field alters the electron energy spectrum by splitting the continuous energy subbands into discrete Landau levels whose arrangement influences the magnitude of the optical gain. In addition, strong effects of band nonparabolicity result in subtle changes in the lasing wavelength at magnetic fields which maximize the gain, thus allowing us to explore the prospects of multi-wavelength emission of the given structure, and achieving resonance with additional compounds, absorbing at wavelengths close to the original one. Numerical results are presented for GaAs/Al(x)Ga(1-x) As based QCL structures designed for operation in the mid-infrared part of the spectrum.",
journal = "Journal of Physics. D: Applied Physics",
title = "Optimization and magnetic-field tunability of quantum cascade laser for applications in trace gas detection and monitoring",
volume = "43",
number = "4",
doi = "10.1088/0022-3727/43/4/045101"
}

Daničić, A., Radovanović, J. V., Milanović, V. B., Indjin, D.,& Ikonić, Z.. (2010). Optimization and magnetic-field tunability of quantum cascade laser for applications in trace gas detection and monitoring. in Journal of Physics. D: Applied Physics, 43(4).
https://doi.org/10.1088/0022-3727/43/4/045101

Daničić A, Radovanović JV, Milanović VB, Indjin D, Ikonić Z. Optimization and magnetic-field tunability of quantum cascade laser for applications in trace gas detection and monitoring. in Journal of Physics. D: Applied Physics. 2010;43(4).
doi:10.1088/0022-3727/43/4/045101 .

Daničić, Aleksandar, Radovanović, Jelena V., Milanović, Vitomir B., Indjin, Dragan, Ikonić, Zoran, "Optimization and magnetic-field tunability of quantum cascade laser for applications in trace gas detection and monitoring" in Journal of Physics. D: Applied Physics, 43, no. 4 (2010),
https://doi.org/10.1088/0022-3727/43/4/045101 . .

TY  - JOUR
AU  - Daničić, Aleksandar
AU  - Radovanović, Jelena V.
AU  - Milanović, Vitomir B.
AU  - Indjin, Dragan
AU  - Ikonić, Zoran
PY  - 2010
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/6870
AB  - We present a method for systematic optimization of quantum cascade laser active region, based on the use of the genetic algorithm. The method aims at obtaining a gain-maximized structure, designed to emit radiation at specified wavelengths suitable for direct absorption by pollutant gasses present in the ambient air. After the initial optimization stage, we introduce a strong external magnetic field to tune the laser output properties and to slightly modify the emission wavelength to match the absorption lines of additional compounds. The magnetic field is applied perpendicularly to the epitaxial layers, thus causing two dimensional continuous energy subbands to split into series of discrete Landau levels. This affects all the relevant relaxation processes in the structure and consequently the lifetime of carriers in the upper laser level. Furthermore, strong effects of band nonparabolicity result in subtle changes of the lasing wavelength at magnetic fields which maximize the gain, thus providing a path for fine tuning of the output radiation properties. Numerical results are presented for GaAs/Al(x)Ga(1-x)As based quantum cascade laser structures designed to emit at particular wavelengths in the mid infrared part of the spectrum.
T2  - Acta Physica Polonica A
T1  - Quantum Cascade Laser Design for Tunable Output at Characteristic Wavelengths in the Mid-Infrared Spectral Range
VL  - 117
IS  - 5
SP  - 772
EP  - 776
DO  - 10.12693/APhysPolA.117.772
ER  - 

@article{
author = "Daničić, Aleksandar and Radovanović, Jelena V. and Milanović, Vitomir B. and Indjin, Dragan and Ikonić, Zoran",
year = "2010",
abstract = "We present a method for systematic optimization of quantum cascade laser active region, based on the use of the genetic algorithm. The method aims at obtaining a gain-maximized structure, designed to emit radiation at specified wavelengths suitable for direct absorption by pollutant gasses present in the ambient air. After the initial optimization stage, we introduce a strong external magnetic field to tune the laser output properties and to slightly modify the emission wavelength to match the absorption lines of additional compounds. The magnetic field is applied perpendicularly to the epitaxial layers, thus causing two dimensional continuous energy subbands to split into series of discrete Landau levels. This affects all the relevant relaxation processes in the structure and consequently the lifetime of carriers in the upper laser level. Furthermore, strong effects of band nonparabolicity result in subtle changes of the lasing wavelength at magnetic fields which maximize the gain, thus providing a path for fine tuning of the output radiation properties. Numerical results are presented for GaAs/Al(x)Ga(1-x)As based quantum cascade laser structures designed to emit at particular wavelengths in the mid infrared part of the spectrum.",
journal = "Acta Physica Polonica A",
title = "Quantum Cascade Laser Design for Tunable Output at Characteristic Wavelengths in the Mid-Infrared Spectral Range",
volume = "117",
number = "5",
pages = "772-776",
doi = "10.12693/APhysPolA.117.772"
}

Daničić, A., Radovanović, J. V., Milanović, V. B., Indjin, D.,& Ikonić, Z.. (2010). Quantum Cascade Laser Design for Tunable Output at Characteristic Wavelengths in the Mid-Infrared Spectral Range. in Acta Physica Polonica A, 117(5), 772-776.
https://doi.org/10.12693/APhysPolA.117.772

Daničić A, Radovanović JV, Milanović VB, Indjin D, Ikonić Z. Quantum Cascade Laser Design for Tunable Output at Characteristic Wavelengths in the Mid-Infrared Spectral Range. in Acta Physica Polonica A. 2010;117(5):772-776.
doi:10.12693/APhysPolA.117.772 .

Daničić, Aleksandar, Radovanović, Jelena V., Milanović, Vitomir B., Indjin, Dragan, Ikonić, Zoran, "Quantum Cascade Laser Design for Tunable Output at Characteristic Wavelengths in the Mid-Infrared Spectral Range" in Acta Physica Polonica A, 117, no. 5 (2010):772-776,
https://doi.org/10.12693/APhysPolA.117.772 . .

TY  - JOUR
AU  - Woellert, A.
AU  - Gligorić, Goran
AU  - Škorić, Miloš M.
AU  - Maluckov, Aleksandra
AU  - Raičević, Nevena
AU  - Daničić, Aleksandar
AU  - Hadžievski, Ljupčo
PY  - 2009
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/6842
AB  - We study the stability of the continuous waves in the pancake shaped dipolar Bose-Einstein condensate trapped in the strong optical lattice potential with the coexisting local (the short-range s-wave) interaction and nonlocal (the dipole-dipole) interactions between the condensate atoms. The system is modeled by two two-dimensional discrete models derived from the Gross-Pitaevskii equation accounting the dipole-dipole interactions: discrete nonlinear Schrodinger equation with cubic nonlinearity and nonpolynomial Schrodinger equation. The corresponding dispersion relations are calculated analytically and the regions of the modulation instability in the parametric space are summarized into the stability diagrams.
T2  - Acta Physica Polonica A
T1  - Modulation Instability of Two-Dimensional Dipolar Bose-Einstein Condensate in a Deep Optical Lattice
VL  - 116
IS  - 4
SP  - 519
EP  - 521
UR  - https://hdl.handle.net/21.15107/rcub_vinar_6842
ER  - 

@article{
author = "Woellert, A. and Gligorić, Goran and Škorić, Miloš M. and Maluckov, Aleksandra and Raičević, Nevena and Daničić, Aleksandar and Hadžievski, Ljupčo",
year = "2009",
abstract = "We study the stability of the continuous waves in the pancake shaped dipolar Bose-Einstein condensate trapped in the strong optical lattice potential with the coexisting local (the short-range s-wave) interaction and nonlocal (the dipole-dipole) interactions between the condensate atoms. The system is modeled by two two-dimensional discrete models derived from the Gross-Pitaevskii equation accounting the dipole-dipole interactions: discrete nonlinear Schrodinger equation with cubic nonlinearity and nonpolynomial Schrodinger equation. The corresponding dispersion relations are calculated analytically and the regions of the modulation instability in the parametric space are summarized into the stability diagrams.",
journal = "Acta Physica Polonica A",
title = "Modulation Instability of Two-Dimensional Dipolar Bose-Einstein Condensate in a Deep Optical Lattice",
volume = "116",
number = "4",
pages = "519-521",
url = "https://hdl.handle.net/21.15107/rcub_vinar_6842"
}

Woellert, A., Gligorić, G., Škorić, M. M., Maluckov, A., Raičević, N., Daničić, A.,& Hadžievski, L.. (2009). Modulation Instability of Two-Dimensional Dipolar Bose-Einstein Condensate in a Deep Optical Lattice. in Acta Physica Polonica A, 116(4), 519-521.
https://hdl.handle.net/21.15107/rcub_vinar_6842

Woellert A, Gligorić G, Škorić MM, Maluckov A, Raičević N, Daničić A, Hadžievski L. Modulation Instability of Two-Dimensional Dipolar Bose-Einstein Condensate in a Deep Optical Lattice. in Acta Physica Polonica A. 2009;116(4):519-521.
https://hdl.handle.net/21.15107/rcub_vinar_6842 .

Woellert, A., Gligorić, Goran, Škorić, Miloš M., Maluckov, Aleksandra, Raičević, Nevena, Daničić, Aleksandar, Hadžievski, Ljupčo, "Modulation Instability of Two-Dimensional Dipolar Bose-Einstein Condensate in a Deep Optical Lattice" in Acta Physica Polonica A, 116, no. 4 (2009):519-521,
https://hdl.handle.net/21.15107/rcub_vinar_6842 .