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  - JOUR
AU  - Radosavljević, Ana
AU  - Radovanović, Jelena V.
AU  - Milanović, Vitomir B.
AU  - Indjin, Dragan
PY  - 2015
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/470
AB  - We propose a method which delivers optimal cubic GaN/AlGaN quantum well profiles such that both the Stark effect and peak intersubband absorption from the ground to the first excited electronic state, in a prescribed range of bias electric fields, are maximized. Our method relies on the Genetic Algorithm which finds globally optimal structures with a predefined number of embedded layers. We investigate simple rectangular quantum wells with embedded step layers for applications in tunable mid-infrared photodetectors. The effects of band nonparabolicity are taken into account to refine our model.
T2  - Optical and Quantum Electronics
T1  - Cubic GaN/AlGaN based quantum wells optimized for applications to tunable mid-infrared photodetectors
VL  - 47
IS  - 4
SP  - 865
EP  - 872
DO  - 10.1007/s11082-014-0016-y
ER  - 

@article{
author = "Radosavljević, Ana and Radovanović, Jelena V. and Milanović, Vitomir B. and Indjin, Dragan",
year = "2015",
abstract = "We propose a method which delivers optimal cubic GaN/AlGaN quantum well profiles such that both the Stark effect and peak intersubband absorption from the ground to the first excited electronic state, in a prescribed range of bias electric fields, are maximized. Our method relies on the Genetic Algorithm which finds globally optimal structures with a predefined number of embedded layers. We investigate simple rectangular quantum wells with embedded step layers for applications in tunable mid-infrared photodetectors. The effects of band nonparabolicity are taken into account to refine our model.",
journal = "Optical and Quantum Electronics",
title = "Cubic GaN/AlGaN based quantum wells optimized for applications to tunable mid-infrared photodetectors",
volume = "47",
number = "4",
pages = "865-872",
doi = "10.1007/s11082-014-0016-y"
}

Radosavljević, A., Radovanović, J. V., Milanović, V. B.,& Indjin, D.. (2015). Cubic GaN/AlGaN based quantum wells optimized for applications to tunable mid-infrared photodetectors. in Optical and Quantum Electronics, 47(4), 865-872.
https://doi.org/10.1007/s11082-014-0016-y

Radosavljević A, Radovanović JV, Milanović VB, Indjin D. Cubic GaN/AlGaN based quantum wells optimized for applications to tunable mid-infrared photodetectors. in Optical and Quantum Electronics. 2015;47(4):865-872.
doi:10.1007/s11082-014-0016-y .

Radosavljević, Ana, Radovanović, Jelena V., Milanović, Vitomir B., Indjin, Dragan, "Cubic GaN/AlGaN based quantum wells optimized for applications to tunable mid-infrared photodetectors" in Optical and Quantum Electronics, 47, no. 4 (2015):865-872,
https://doi.org/10.1007/s11082-014-0016-y . .

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  - JOUR
AU  - Radovanović, Jelena V.
AU  - Danici, A.
AU  - Milanović, Vitomir B.
AU  - Indjin, Dragan
AU  - Ikonić, Zoran
PY  - 2011
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/6915
AB  - We present a detailed analysis of GaAs/AlGaAs terahertz quantum cascade laser in the presence of an intense external magnetic field. One of the objectives in further development of THz quantum cascade laser is the realization of structures operating at higher temperatures. This is difficult to obtain as the operating photon emission energy is smaller than the longitudinal-optical phonon energy in the semiconductor material. With increased temperature, electrons in the upper radiative state gain sufficient in-plane energy to emit an longitudinal-optical phonon, which represents a non-radiative scattering and reduces the optical gain. By applying strong magnetic field, two-dimensional continuous energy subbands become split into series of discrete Landau levels, and at particular values of B it is possible to quench these non-radiative channels. Numerical simulations are performed on two-well design quantum cascade laser operating at 4.6 THz, implemented in CaAs/Al(0.15)Ga(0.85)As, and the magnetic field is perpendicular to the epitaxial layers. Strong oscillations of carrier lifetimes for the upper state of the laser transition, as a function of magnetic field are observed, which can be attributed to interface roughness scattering and longitudinal-optical phonon scattering between Landau levels.
T2  - Acta Physica Polonica A
T1  - Inter-Landau Level Scattering Processes in Magnetic Field Assisted THz Quantum Cascade Laser
VL  - 120
IS  - 2
SP  - 227
EP  - 230
DO  - 10.12693/APhysPolA.120.227
ER  - 

@article{
author = "Radovanović, Jelena V. and Danici, A. and Milanović, Vitomir B. and Indjin, Dragan and Ikonić, Zoran",
year = "2011",
abstract = "We present a detailed analysis of GaAs/AlGaAs terahertz quantum cascade laser in the presence of an intense external magnetic field. One of the objectives in further development of THz quantum cascade laser is the realization of structures operating at higher temperatures. This is difficult to obtain as the operating photon emission energy is smaller than the longitudinal-optical phonon energy in the semiconductor material. With increased temperature, electrons in the upper radiative state gain sufficient in-plane energy to emit an longitudinal-optical phonon, which represents a non-radiative scattering and reduces the optical gain. By applying strong magnetic field, two-dimensional continuous energy subbands become split into series of discrete Landau levels, and at particular values of B it is possible to quench these non-radiative channels. Numerical simulations are performed on two-well design quantum cascade laser operating at 4.6 THz, implemented in CaAs/Al(0.15)Ga(0.85)As, and the magnetic field is perpendicular to the epitaxial layers. Strong oscillations of carrier lifetimes for the upper state of the laser transition, as a function of magnetic field are observed, which can be attributed to interface roughness scattering and longitudinal-optical phonon scattering between Landau levels.",
journal = "Acta Physica Polonica A",
title = "Inter-Landau Level Scattering Processes in Magnetic Field Assisted THz Quantum Cascade Laser",
volume = "120",
number = "2",
pages = "227-230",
doi = "10.12693/APhysPolA.120.227"
}

Radovanović, J. V., Danici, A., Milanović, V. B., Indjin, D.,& Ikonić, Z.. (2011). Inter-Landau Level Scattering Processes in Magnetic Field Assisted THz Quantum Cascade Laser. in Acta Physica Polonica A, 120(2), 227-230.
https://doi.org/10.12693/APhysPolA.120.227

Radovanović JV, Danici A, Milanović VB, Indjin D, Ikonić Z. Inter-Landau Level Scattering Processes in Magnetic Field Assisted THz Quantum Cascade Laser. in Acta Physica Polonica A. 2011;120(2):227-230.
doi:10.12693/APhysPolA.120.227 .

Radovanović, Jelena V., Danici, A., Milanović, Vitomir B., Indjin, Dragan, Ikonić, Zoran, "Inter-Landau Level Scattering Processes in Magnetic Field Assisted THz Quantum Cascade Laser" in Acta Physica Polonica A, 120, no. 2 (2011):227-230,
https://doi.org/10.12693/APhysPolA.120.227 . .

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 . .