TY  - CONF
AU  - Davidović, Miloš
AU  - Kleut, Duška
AU  - Davidović, Milena D.
AU  - Stojanović, Danka B.
AU  - Jovašević-Stojanović, Milena
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/13046
AB  - Atmospheric aerosols in urban areas typically consist of particles of different diameters, which can range in size from a few nanometers to a few micrometers and can have a strong impact on human health [1,2]. This motivates the need to measure aerosol concentration accurately, but it is often also necessary to combine results from several instruments, with fundamentally different measurement principles. In this work, methods based on the measurement of the electrical mobility of particles, for the range of diameters from 10nm to 420nm, and the measurement of the equivalent optical diameter, for the range of diameters from 300nm to 10um, were used. Combining the overlapping region in two size distribution spectra can be used to infer equivalent optical properties of the ambient aerosol, and examples of measured and combined spectra in several urban hot spots in Bay of Kotor are analyzed in some detail. These examples will illustrate several aspects of urban aerosol properties not readily available in a typical regulatory monitoring setting, such as distribution of modes in number and mass concentration, as well as optical properties of measured aerosol.  As the main result, examples of combining particle size spectrums are presented. In the process of combining the particle size spectra, it is possible to modify the distribution obtained by optical measurements by searching for the optimal value of the refractive index of the particles to obtain the best possible agreement with the size distribution obtained by measuring the electrical mobility. An equivalent refractive index as well as the equivalent shape factor of the ambient aerosol is obtained using Mie scattering theory as a theoretical framework [3]. The measurement results from the mobile monitoring campaign in Bay of Kotor in 2017 were used to elucidate the main principles of size spectrum combination, as well as to showcase diversity of equivalent optical properties of urban aerosols.
PB  - Belgrade : Institute of Physics
C3  - 16th Photonics Workshop : Book of abstracts
T1  - Combining size distribution spectrums of ambient aerosols using equivalent optical properties of nanosized particles – selected examples from the Bay of Kotor
SP  - 26
EP  - 26
UR  - https://hdl.handle.net/21.15107/rcub_vinar_13046
ER  - 

@conference{
author = "Davidović, Miloš and Kleut, Duška and Davidović, Milena D. and Stojanović, Danka B. and Jovašević-Stojanović, Milena",
year = "2023",
abstract = "Atmospheric aerosols in urban areas typically consist of particles of different diameters, which can range in size from a few nanometers to a few micrometers and can have a strong impact on human health [1,2]. This motivates the need to measure aerosol concentration accurately, but it is often also necessary to combine results from several instruments, with fundamentally different measurement principles. In this work, methods based on the measurement of the electrical mobility of particles, for the range of diameters from 10nm to 420nm, and the measurement of the equivalent optical diameter, for the range of diameters from 300nm to 10um, were used. Combining the overlapping region in two size distribution spectra can be used to infer equivalent optical properties of the ambient aerosol, and examples of measured and combined spectra in several urban hot spots in Bay of Kotor are analyzed in some detail. These examples will illustrate several aspects of urban aerosol properties not readily available in a typical regulatory monitoring setting, such as distribution of modes in number and mass concentration, as well as optical properties of measured aerosol.  As the main result, examples of combining particle size spectrums are presented. In the process of combining the particle size spectra, it is possible to modify the distribution obtained by optical measurements by searching for the optimal value of the refractive index of the particles to obtain the best possible agreement with the size distribution obtained by measuring the electrical mobility. An equivalent refractive index as well as the equivalent shape factor of the ambient aerosol is obtained using Mie scattering theory as a theoretical framework [3]. The measurement results from the mobile monitoring campaign in Bay of Kotor in 2017 were used to elucidate the main principles of size spectrum combination, as well as to showcase diversity of equivalent optical properties of urban aerosols.",
publisher = "Belgrade : Institute of Physics",
journal = "16th Photonics Workshop : Book of abstracts",
title = "Combining size distribution spectrums of ambient aerosols using equivalent optical properties of nanosized particles – selected examples from the Bay of Kotor",
pages = "26-26",
url = "https://hdl.handle.net/21.15107/rcub_vinar_13046"
}

Davidović, M., Kleut, D., Davidović, M. D., Stojanović, D. B.,& Jovašević-Stojanović, M.. (2023). Combining size distribution spectrums of ambient aerosols using equivalent optical properties of nanosized particles – selected examples from the Bay of Kotor. in 16th Photonics Workshop : Book of abstracts
Belgrade : Institute of Physics., 26-26.
https://hdl.handle.net/21.15107/rcub_vinar_13046

Davidović M, Kleut D, Davidović MD, Stojanović DB, Jovašević-Stojanović M. Combining size distribution spectrums of ambient aerosols using equivalent optical properties of nanosized particles – selected examples from the Bay of Kotor. in 16th Photonics Workshop : Book of abstracts. 2023;:26-26.
https://hdl.handle.net/21.15107/rcub_vinar_13046 .

Davidović, Miloš, Kleut, Duška, Davidović, Milena D., Stojanović, Danka B., Jovašević-Stojanović, Milena, "Combining size distribution spectrums of ambient aerosols using equivalent optical properties of nanosized particles – selected examples from the Bay of Kotor" in 16th Photonics Workshop : Book of abstracts (2023):26-26,
https://hdl.handle.net/21.15107/rcub_vinar_13046 .

TY  - CONF
AU  - Ozyuzer, Lutfi
AU  - Demirhan, Yasemin
AU  - Altan, Hakan
AU  - Ralević, Uroš
AU  - Ozdemir, Mehtap
AU  - Aygun, Gulnur
AU  - Stojanović, Danka B.
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/13048
AB  - There are exceptional advantages in the region where Terahertz (THz) frequency takes place that could be identified as; a non-ionizing bio-innocuous property, transparent characteristics in cardboard or textiles, and extremely discriminating absorption spectral lines which can provide a “genetic code” of various bio-materials. [1,2]. The resonant effects at various terahertz frequencies that were displayed by metamaterials have created to accomplish a very important situation. Metamaterials are virtually desirable platforms for investigating chiral effects.  In order to enhance these effects, producing the tunable chiral devices attracted lots of attention. Among the phase change materials for chiral metamaterials, graphene is a promising candidate due to its astonishing properties specifically in the THz and far infrared region.  In this study, a chiral metamaterial gammadion structure is designed and fabricated on both sides of the sapphire substrates. A commercial COMSOL and CST Microwave Studio programs are used to design and optimize the chiral metamaterial. Numerical simulations are based on the interaction of the chiral structure with linearly and circularly polarized light. In the experimental side, a resistive evaporation and dc magnetron sputtering method is used for the deposition of gold and Sb2Se3 films respectively. A single layer graphene is used, that is grown on a copper foil by chemical vapor deposition. The thin graphene layer transferred on the Sb2Se3 coated sapphire substrates. The conventional UV lithography and ion beam etching techniques are used for patterning process. The THz characterization measurements were performed in order to assess the THz frequency response and to demonstrate the dynamically tunable chiroptical response using optical pumping [3,4]. The active polarization manipulation capability of the Sb2Se3/graphene chiral metamaterial with frequency tunability are investigated both numerically and experimentally.
PB  - Belgrade : Institute of Physics
C3  - 16th Photonics Workshop : Book of abstracts
T1  - Chiral Devices for Terahertz Waves Based on Tunable Metamaterials
SP  - 49
EP  - 49
UR  - https://hdl.handle.net/21.15107/rcub_vinar_13048
ER  - 

@conference{
author = "Ozyuzer, Lutfi and Demirhan, Yasemin and Altan, Hakan and Ralević, Uroš and Ozdemir, Mehtap and Aygun, Gulnur and Stojanović, Danka B.",
year = "2023",
abstract = "There are exceptional advantages in the region where Terahertz (THz) frequency takes place that could be identified as; a non-ionizing bio-innocuous property, transparent characteristics in cardboard or textiles, and extremely discriminating absorption spectral lines which can provide a “genetic code” of various bio-materials. [1,2]. The resonant effects at various terahertz frequencies that were displayed by metamaterials have created to accomplish a very important situation. Metamaterials are virtually desirable platforms for investigating chiral effects.  In order to enhance these effects, producing the tunable chiral devices attracted lots of attention. Among the phase change materials for chiral metamaterials, graphene is a promising candidate due to its astonishing properties specifically in the THz and far infrared region.  In this study, a chiral metamaterial gammadion structure is designed and fabricated on both sides of the sapphire substrates. A commercial COMSOL and CST Microwave Studio programs are used to design and optimize the chiral metamaterial. Numerical simulations are based on the interaction of the chiral structure with linearly and circularly polarized light. In the experimental side, a resistive evaporation and dc magnetron sputtering method is used for the deposition of gold and Sb2Se3 films respectively. A single layer graphene is used, that is grown on a copper foil by chemical vapor deposition. The thin graphene layer transferred on the Sb2Se3 coated sapphire substrates. The conventional UV lithography and ion beam etching techniques are used for patterning process. The THz characterization measurements were performed in order to assess the THz frequency response and to demonstrate the dynamically tunable chiroptical response using optical pumping [3,4]. The active polarization manipulation capability of the Sb2Se3/graphene chiral metamaterial with frequency tunability are investigated both numerically and experimentally.",
publisher = "Belgrade : Institute of Physics",
journal = "16th Photonics Workshop : Book of abstracts",
title = "Chiral Devices for Terahertz Waves Based on Tunable Metamaterials",
pages = "49-49",
url = "https://hdl.handle.net/21.15107/rcub_vinar_13048"
}

Ozyuzer, L., Demirhan, Y., Altan, H., Ralević, U., Ozdemir, M., Aygun, G.,& Stojanović, D. B.. (2023). Chiral Devices for Terahertz Waves Based on Tunable Metamaterials. in 16th Photonics Workshop : Book of abstracts
Belgrade : Institute of Physics., 49-49.
https://hdl.handle.net/21.15107/rcub_vinar_13048

Ozyuzer L, Demirhan Y, Altan H, Ralević U, Ozdemir M, Aygun G, Stojanović DB. Chiral Devices for Terahertz Waves Based on Tunable Metamaterials. in 16th Photonics Workshop : Book of abstracts. 2023;:49-49.
https://hdl.handle.net/21.15107/rcub_vinar_13048 .

Ozyuzer, Lutfi, Demirhan, Yasemin, Altan, Hakan, Ralević, Uroš, Ozdemir, Mehtap, Aygun, Gulnur, Stojanović, Danka B., "Chiral Devices for Terahertz Waves Based on Tunable Metamaterials" in 16th Photonics Workshop : Book of abstracts (2023):49-49,
https://hdl.handle.net/21.15107/rcub_vinar_13048 .

TY  - CONF
AU  - Stojanović, Danka B.
AU  - Kleut, Duška
AU  - Davidović, Miloš
AU  - Lepioufle, Jean-Marie
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/13047
AB  - Particulate matter (PM) in air has been proven to be hazardous to human health. Until recently, monitoring of air quality has been done by professional agencies. Nowadays, the availability of portable, low cost microsensor devices and the exponential growth of IoT (Internet of Things) in everyday life has enabled widespread monitoring of air quality among all citizens.[1]. For PM measurements, optical sensors measure light scattering by particles carried in an air stream through a light beam, which is converted by computation to equivalent mass concentration. Light scattering is strongly affected by parameters such as particle density, particle hygroscopicity, refraction index, and particle composition [2]. In this study, we measured PM 2.5 by seven AQ MESH low-cost optical sensors and compared the measured data with the ones obtained from the reference monitoring station (SEPA). Could we, by a sequence of low-processing data enrichment and a simple calibration method, reach an accuracy as close as a calibration based on machine learning? To answer this question, we used low-processing data enrichment such as resampling, encoding periodic timerelated features and making a composition of the initial low-cost signal at different time scales. We compared two algorithms for the calibration: multivariate linear regression and random forest. The results gave promising results and encouraged us in researching further about signal low-processing to achieve the required quality of data from low-cost sensor devices monitoring air quality [3].
PB  - Belgrade : Institute of Physics
C3  - 16th Photonics Workshop : Book of abstracts
T1  - Data enrichment and calibration for PM 2.5 low-cost optical sensors
SP  - 40
EP  - 40
UR  - https://hdl.handle.net/21.15107/rcub_vinar_13047
ER  - 

@conference{
author = "Stojanović, Danka B. and Kleut, Duška and Davidović, Miloš and Lepioufle, Jean-Marie",
year = "2023",
abstract = "Particulate matter (PM) in air has been proven to be hazardous to human health. Until recently, monitoring of air quality has been done by professional agencies. Nowadays, the availability of portable, low cost microsensor devices and the exponential growth of IoT (Internet of Things) in everyday life has enabled widespread monitoring of air quality among all citizens.[1]. For PM measurements, optical sensors measure light scattering by particles carried in an air stream through a light beam, which is converted by computation to equivalent mass concentration. Light scattering is strongly affected by parameters such as particle density, particle hygroscopicity, refraction index, and particle composition [2]. In this study, we measured PM 2.5 by seven AQ MESH low-cost optical sensors and compared the measured data with the ones obtained from the reference monitoring station (SEPA). Could we, by a sequence of low-processing data enrichment and a simple calibration method, reach an accuracy as close as a calibration based on machine learning? To answer this question, we used low-processing data enrichment such as resampling, encoding periodic timerelated features and making a composition of the initial low-cost signal at different time scales. We compared two algorithms for the calibration: multivariate linear regression and random forest. The results gave promising results and encouraged us in researching further about signal low-processing to achieve the required quality of data from low-cost sensor devices monitoring air quality [3].",
publisher = "Belgrade : Institute of Physics",
journal = "16th Photonics Workshop : Book of abstracts",
title = "Data enrichment and calibration for PM 2.5 low-cost optical sensors",
pages = "40-40",
url = "https://hdl.handle.net/21.15107/rcub_vinar_13047"
}

Stojanović, D. B., Kleut, D., Davidović, M.,& Lepioufle, J.. (2023). Data enrichment and calibration for PM 2.5 low-cost optical sensors. in 16th Photonics Workshop : Book of abstracts
Belgrade : Institute of Physics., 40-40.
https://hdl.handle.net/21.15107/rcub_vinar_13047

Stojanović DB, Kleut D, Davidović M, Lepioufle J. Data enrichment and calibration for PM 2.5 low-cost optical sensors. in 16th Photonics Workshop : Book of abstracts. 2023;:40-40.
https://hdl.handle.net/21.15107/rcub_vinar_13047 .

Stojanović, Danka B., Kleut, Duška, Davidović, Miloš, Lepioufle, Jean-Marie, "Data enrichment and calibration for PM 2.5 low-cost optical sensors" in 16th Photonics Workshop : Book of abstracts (2023):40-40,
https://hdl.handle.net/21.15107/rcub_vinar_13047 .

TY  - JOUR
AU  - De Vito, Saverio
AU  - D’Elia, Gerardo
AU  - Ferlito, Sergio
AU  - Di Francia, Girolamo
AU  - Davidović, Miloš
AU  - Kleut, Duška
AU  - Stojanović, Danka
AU  - Jovašević-Stojanović, Milena
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/12046
AB  - Scalable and effective calibration is a fundamental requirement for Low Cost Air Quality Monitoring Systems and will enable accurate and pervasive monitoring in cities. Suffering from environmental interferences and fabrication variance, these devices need to encompass sensors specific and complex calibration processes for reaching a sufficient accuracy to be deployed as indicative measurement devices in Air Quality (AQ) monitoring networks. Concept and sensor drift often force calibration process to be frequently repeated. These issues lead to unbearable calibration costs which denies their massive deployment when accuracy is a concern. In this work, We propose a zero transfer samples, global calibration methodology as a technological enabler for IoT AQ multisensory devices which relies on low cost Particulate Matter (PM) sensors. This methodology is based on field recorded responses from a limited number of IoT AQ multisensors units and machine learning concepts and can be universally applied to all units of the same type. A multi season test campaign shown that, when applied to different sensors, this methodology performances match those of state of the art methodology which requires to derive different calibration parameters for each different unit. If confirmed, these results show that, when properly derived, a global calibration law can be exploited for a large number of networked devices with dramatic cost reduction eventually allowing massive deployment of accurate IoT AQ monitoring devices. Furthermore, this calibration model could be easily embedded on board of the device or implemented on the edge allowing immediate access to accurate readings for personal exposure monitor applications as well as reducing long range data transfer needs.
T2  - IEEE Transactions on Instrumentation and Measurement
T1  - A Global Multi-Unit Calibration as a Method for Large Scale IoT Particulate Matter Monitoring Systems Deployments
SP  - 1
EP  - 1
DO  - 10.1109/TIM.2023.3331428
ER  - 

@article{
author = "De Vito, Saverio and D’Elia, Gerardo and Ferlito, Sergio and Di Francia, Girolamo and Davidović, Miloš and Kleut, Duška and Stojanović, Danka and Jovašević-Stojanović, Milena",
year = "2023",
abstract = "Scalable and effective calibration is a fundamental requirement for Low Cost Air Quality Monitoring Systems and will enable accurate and pervasive monitoring in cities. Suffering from environmental interferences and fabrication variance, these devices need to encompass sensors specific and complex calibration processes for reaching a sufficient accuracy to be deployed as indicative measurement devices in Air Quality (AQ) monitoring networks. Concept and sensor drift often force calibration process to be frequently repeated. These issues lead to unbearable calibration costs which denies their massive deployment when accuracy is a concern. In this work, We propose a zero transfer samples, global calibration methodology as a technological enabler for IoT AQ multisensory devices which relies on low cost Particulate Matter (PM) sensors. This methodology is based on field recorded responses from a limited number of IoT AQ multisensors units and machine learning concepts and can be universally applied to all units of the same type. A multi season test campaign shown that, when applied to different sensors, this methodology performances match those of state of the art methodology which requires to derive different calibration parameters for each different unit. If confirmed, these results show that, when properly derived, a global calibration law can be exploited for a large number of networked devices with dramatic cost reduction eventually allowing massive deployment of accurate IoT AQ monitoring devices. Furthermore, this calibration model could be easily embedded on board of the device or implemented on the edge allowing immediate access to accurate readings for personal exposure monitor applications as well as reducing long range data transfer needs.",
journal = "IEEE Transactions on Instrumentation and Measurement",
title = "A Global Multi-Unit Calibration as a Method for Large Scale IoT Particulate Matter Monitoring Systems Deployments",
pages = "1-1",
doi = "10.1109/TIM.2023.3331428"
}

De Vito, S., D’Elia, G., Ferlito, S., Di Francia, G., Davidović, M., Kleut, D., Stojanović, D.,& Jovašević-Stojanović, M.. (2023). A Global Multi-Unit Calibration as a Method for Large Scale IoT Particulate Matter Monitoring Systems Deployments. in IEEE Transactions on Instrumentation and Measurement, 1-1.
https://doi.org/10.1109/TIM.2023.3331428

De Vito S, D’Elia G, Ferlito S, Di Francia G, Davidović M, Kleut D, Stojanović D, Jovašević-Stojanović M. A Global Multi-Unit Calibration as a Method for Large Scale IoT Particulate Matter Monitoring Systems Deployments. in IEEE Transactions on Instrumentation and Measurement. 2023;:1-1.
doi:10.1109/TIM.2023.3331428 .

De Vito, Saverio, D’Elia, Gerardo, Ferlito, Sergio, Di Francia, Girolamo, Davidović, Miloš, Kleut, Duška, Stojanović, Danka, Jovašević-Stojanović, Milena, "A Global Multi-Unit Calibration as a Method for Large Scale IoT Particulate Matter Monitoring Systems Deployments" in IEEE Transactions on Instrumentation and Measurement (2023):1-1,
https://doi.org/10.1109/TIM.2023.3331428 . .

TY  - JOUR
AU  - Stojanović, Danka
AU  - Kleut, Duška
AU  - Davidović, Miloš
AU  - de Vito, Saverio
AU  - Jovašević-Stojanović, Milena
AU  - Bartonova, Alena
AU  - Lepioufle, Jean-Marie
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/12957
AB  - Particulate matter (PM) in air has been proven to be hazardous to human health. Here we focused on analysis of PM data we obtained from the same campaign which was presented in our previous study. Multivariate linear and random forest models were used for the calibration and analysis. In our linear regression model the inputs were PM, temperature and humidity measured with low-cost sensors, and the target was the reference PM measurements obtained from SEPA in the same timeframe.
T2  - Thermal Science
T1  - Low-processing data enrichment and calibration for PM2.5 low-cost sensors
VL  - 27
IS  - 3 Part B
SP  - 2229
EP  - 2240
DO  - 10.2298/TSCI221109221S
ER  - 

@article{
author = "Stojanović, Danka and Kleut, Duška and Davidović, Miloš and de Vito, Saverio and Jovašević-Stojanović, Milena and Bartonova, Alena and Lepioufle, Jean-Marie",
year = "2023",
abstract = "Particulate matter (PM) in air has been proven to be hazardous to human health. Here we focused on analysis of PM data we obtained from the same campaign which was presented in our previous study. Multivariate linear and random forest models were used for the calibration and analysis. In our linear regression model the inputs were PM, temperature and humidity measured with low-cost sensors, and the target was the reference PM measurements obtained from SEPA in the same timeframe.",
journal = "Thermal Science",
title = "Low-processing data enrichment and calibration for PM2.5 low-cost sensors",
volume = "27",
number = "3 Part B",
pages = "2229-2240",
doi = "10.2298/TSCI221109221S"
}

Stojanović, D., Kleut, D., Davidović, M., de Vito, S., Jovašević-Stojanović, M., Bartonova, A.,& Lepioufle, J.. (2023). Low-processing data enrichment and calibration for PM2.5 low-cost sensors. in Thermal Science, 27(3 Part B), 2229-2240.
https://doi.org/10.2298/TSCI221109221S

Stojanović D, Kleut D, Davidović M, de Vito S, Jovašević-Stojanović M, Bartonova A, Lepioufle J. Low-processing data enrichment and calibration for PM2.5 low-cost sensors. in Thermal Science. 2023;27(3 Part B):2229-2240.
doi:10.2298/TSCI221109221S .

Stojanović, Danka, Kleut, Duška, Davidović, Miloš, de Vito, Saverio, Jovašević-Stojanović, Milena, Bartonova, Alena, Lepioufle, Jean-Marie, "Low-processing data enrichment and calibration for PM2.5 low-cost sensors" in Thermal Science, 27, no. 3 Part B (2023):2229-2240,
https://doi.org/10.2298/TSCI221109221S . .

TY  - CONF
AU  - Stojanović, Danka
AU  - Ralević, U.
AU  - Demirhan, Y.
AU  - Aygun, G.
AU  - Ozyuzer, L.
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/11824
AB  - Metamaterials that respond resonantly in interaction with the terahertz (THz) electromagnetic waves are significant for the achievement of diverse optical functionalities in THz spectral range [1]. Also, they are virtually desirable platforms for investigating chiral effects which rise due to different interaction of metamaterials with left and right circularly polarized light [2,3]. Light polarization is an important feature of electromagnetic waves and manipulation of polarization plays pivotal role in various areas such as communications, imaging and sensing. One of potential applications of the THz metadevices is for protein quality control in the biotechnology or food industries [4]. Chiral properties of metamaterial can be modified via different external influences, such as by changing the interlayer twist angle, adding a dielectric spacer, or modulating its thickness. Twisting or rotating achiral layered structures in parallel planes enables engineering of the extrinsic chirality and consequential optical performance. For example, the twist angle from counterclockwise rotation of an upper layer with respect to the one under it, leads to a left-handed stacking geometry [5]. In this study, we performed numerical simulations of the metamaterial structure in terahertz frequency range, 0.25-0.75 THz. The numerical simulations were done for the case of two parallel gold rosettes on sapphire substrates in which we analyzed the influence of rotating one rosette with respect to the another on chiral properties. Two geometries of the rosette based structures were studied. First geometry is based on resonator which consists of two same parallel rosettes and the second one of two parallel rosettes, but one of them is trimmed.
PB  - Belgrade : Vinča Institute of Nuclear Sciences
C3  - PHOTONICA2023 : 9th International School and Conference on Photonics : book of abstracts; August 28 - September 1, 2023; Belgrade
T1  - Rosette based metamaterial for circularly polarized terahertz waves manipulation
SP  - 132
EP  - 132
UR  - https://hdl.handle.net/21.15107/rcub_vinar_11824
ER  - 

@conference{
author = "Stojanović, Danka and Ralević, U. and Demirhan, Y. and Aygun, G. and Ozyuzer, L.",
year = "2023",
abstract = "Metamaterials that respond resonantly in interaction with the terahertz (THz) electromagnetic waves are significant for the achievement of diverse optical functionalities in THz spectral range [1]. Also, they are virtually desirable platforms for investigating chiral effects which rise due to different interaction of metamaterials with left and right circularly polarized light [2,3]. Light polarization is an important feature of electromagnetic waves and manipulation of polarization plays pivotal role in various areas such as communications, imaging and sensing. One of potential applications of the THz metadevices is for protein quality control in the biotechnology or food industries [4]. Chiral properties of metamaterial can be modified via different external influences, such as by changing the interlayer twist angle, adding a dielectric spacer, or modulating its thickness. Twisting or rotating achiral layered structures in parallel planes enables engineering of the extrinsic chirality and consequential optical performance. For example, the twist angle from counterclockwise rotation of an upper layer with respect to the one under it, leads to a left-handed stacking geometry [5]. In this study, we performed numerical simulations of the metamaterial structure in terahertz frequency range, 0.25-0.75 THz. The numerical simulations were done for the case of two parallel gold rosettes on sapphire substrates in which we analyzed the influence of rotating one rosette with respect to the another on chiral properties. Two geometries of the rosette based structures were studied. First geometry is based on resonator which consists of two same parallel rosettes and the second one of two parallel rosettes, but one of them is trimmed.",
publisher = "Belgrade : Vinča Institute of Nuclear Sciences",
journal = "PHOTONICA2023 : 9th International School and Conference on Photonics : book of abstracts; August 28 - September 1, 2023; Belgrade",
title = "Rosette based metamaterial for circularly polarized terahertz waves manipulation",
pages = "132-132",
url = "https://hdl.handle.net/21.15107/rcub_vinar_11824"
}

Stojanović, D., Ralević, U., Demirhan, Y., Aygun, G.,& Ozyuzer, L.. (2023). Rosette based metamaterial for circularly polarized terahertz waves manipulation. in PHOTONICA2023 : 9th International School and Conference on Photonics : book of abstracts; August 28 - September 1, 2023; Belgrade
Belgrade : Vinča Institute of Nuclear Sciences., 132-132.
https://hdl.handle.net/21.15107/rcub_vinar_11824

Stojanović D, Ralević U, Demirhan Y, Aygun G, Ozyuzer L. Rosette based metamaterial for circularly polarized terahertz waves manipulation. in PHOTONICA2023 : 9th International School and Conference on Photonics : book of abstracts; August 28 - September 1, 2023; Belgrade. 2023;:132-132.
https://hdl.handle.net/21.15107/rcub_vinar_11824 .

Stojanović, Danka, Ralević, U., Demirhan, Y., Aygun, G., Ozyuzer, L., "Rosette based metamaterial for circularly polarized terahertz waves manipulation" in PHOTONICA2023 : 9th International School and Conference on Photonics : book of abstracts; August 28 - September 1, 2023; Belgrade (2023):132-132,
https://hdl.handle.net/21.15107/rcub_vinar_11824 .

TY  - JOUR
AU  - Stojanović, Danka B.
AU  - Gligorić, Goran
AU  - Beličev, Petra
AU  - Belić, Milivoj R.
AU  - Hadžievski, Ljupčo
PY  - 2021
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/9769
AB  - In this article, we propose a chiral metamaterial absorber based on four rotated twisted closed ring resonators operative in terahertz frequency range. The resonant features are analyzed by electric field amplitude distributions, and surface currents flow generated by the interaction of circularly polarized waves with the chiral structure. The highest field amplitudes at the fundamental resonance are obtained at the gap region of the resonator. Therefore, the efficiency of the proposed absorber is determined through response of absorption spectrum around this resonance with variation of geometrical parameters of the structure. Significant increase of absorption of the left circularly polarized light is obtained with variation of the period size of structure. Consequently, huge circular dichroism, and near-unity polarization selective absorption have been provided. This makes the proposed chiral structure a good candidate for designing circular polarization selective absorber. © 2020 IEEE.
T2  - IEEE Journal of Selected Topics in Quantum Electronics
T2  - IEEE Journal of Selected Topics in Quantum Electronics
T1  - Circular polarization selective metamaterial absorber in terahertz frequency range
VL  - 27
IS  - 1
DO  - 10.1109/JSTQE.2020.3024570
ER  - 

@article{
author = "Stojanović, Danka B. and Gligorić, Goran and Beličev, Petra and Belić, Milivoj R. and Hadžievski, Ljupčo",
year = "2021",
abstract = "In this article, we propose a chiral metamaterial absorber based on four rotated twisted closed ring resonators operative in terahertz frequency range. The resonant features are analyzed by electric field amplitude distributions, and surface currents flow generated by the interaction of circularly polarized waves with the chiral structure. The highest field amplitudes at the fundamental resonance are obtained at the gap region of the resonator. Therefore, the efficiency of the proposed absorber is determined through response of absorption spectrum around this resonance with variation of geometrical parameters of the structure. Significant increase of absorption of the left circularly polarized light is obtained with variation of the period size of structure. Consequently, huge circular dichroism, and near-unity polarization selective absorption have been provided. This makes the proposed chiral structure a good candidate for designing circular polarization selective absorber. © 2020 IEEE.",
journal = "IEEE Journal of Selected Topics in Quantum Electronics, IEEE Journal of Selected Topics in Quantum Electronics",
title = "Circular polarization selective metamaterial absorber in terahertz frequency range",
volume = "27",
number = "1",
doi = "10.1109/JSTQE.2020.3024570"
}

Stojanović, D. B., Gligorić, G., Beličev, P., Belić, M. R.,& Hadžievski, L.. (2021). Circular polarization selective metamaterial absorber in terahertz frequency range. in IEEE Journal of Selected Topics in Quantum Electronics, 27(1).
https://doi.org/10.1109/JSTQE.2020.3024570

Stojanović DB, Gligorić G, Beličev P, Belić MR, Hadžievski L. Circular polarization selective metamaterial absorber in terahertz frequency range. in IEEE Journal of Selected Topics in Quantum Electronics. 2021;27(1).
doi:10.1109/JSTQE.2020.3024570 .

Stojanović, Danka B., Gligorić, Goran, Beličev, Petra, Belić, Milivoj R., Hadžievski, Ljupčo, "Circular polarization selective metamaterial absorber in terahertz frequency range" in IEEE Journal of Selected Topics in Quantum Electronics, 27, no. 1 (2021),
https://doi.org/10.1109/JSTQE.2020.3024570 . .

TY  - JOUR
AU  - Isić, Goran
AU  - Zografopoulos, Dimitrios C.
AU  - Stojanović, Danka
AU  - Vasić, Borislav Z.
AU  - Belić, Milivoj R.
PY  - 2021
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/9071
AB  - Beam steering is one of the prevailing functions performed by electromagnetic metasurfaces. Its efficiency depends on a large number of physical parameters associated with resonant elements comprising the metasurface and is thus notoriously difficult to optimize. Here we formulate a theoretical model for evaluating the diffraction efficiency of an array of lossy resonant elements whose spectral response is dominated by the coupling between a leaky eigenmode and a single incoming/outgoing channel. We use it to deduce a formula for the maximum attainable diffraction efficiency and the gradient parameter profile for which it is achieved. The optimization procedure is demonstrated on the example of an electrically tunable liquid-crystal terahertz beam steering metasurface. Finally, the proposed model is benchmarked against rigorous metasurface simulations. © 1995-2012 IEEE.
PB  - IEEE
T2  - IEEE Journal of Selected Topics in Quantum Electronics
T1  - Beam Steering Efficiency in Resonant Reflective Metasurfaces
VL  - 27
IS  - 1
SP  - 9130831
DO  - 10.1109/JSTQE.2020.3006368
ER  - 

@article{
author = "Isić, Goran and Zografopoulos, Dimitrios C. and Stojanović, Danka and Vasić, Borislav Z. and Belić, Milivoj R.",
year = "2021",
abstract = "Beam steering is one of the prevailing functions performed by electromagnetic metasurfaces. Its efficiency depends on a large number of physical parameters associated with resonant elements comprising the metasurface and is thus notoriously difficult to optimize. Here we formulate a theoretical model for evaluating the diffraction efficiency of an array of lossy resonant elements whose spectral response is dominated by the coupling between a leaky eigenmode and a single incoming/outgoing channel. We use it to deduce a formula for the maximum attainable diffraction efficiency and the gradient parameter profile for which it is achieved. The optimization procedure is demonstrated on the example of an electrically tunable liquid-crystal terahertz beam steering metasurface. Finally, the proposed model is benchmarked against rigorous metasurface simulations. © 1995-2012 IEEE.",
publisher = "IEEE",
journal = "IEEE Journal of Selected Topics in Quantum Electronics",
title = "Beam Steering Efficiency in Resonant Reflective Metasurfaces",
volume = "27",
number = "1",
pages = "9130831",
doi = "10.1109/JSTQE.2020.3006368"
}

Isić, G., Zografopoulos, D. C., Stojanović, D., Vasić, B. Z.,& Belić, M. R.. (2021). Beam Steering Efficiency in Resonant Reflective Metasurfaces. in IEEE Journal of Selected Topics in Quantum Electronics
IEEE., 27(1), 9130831.
https://doi.org/10.1109/JSTQE.2020.3006368

Isić G, Zografopoulos DC, Stojanović D, Vasić BZ, Belić MR. Beam Steering Efficiency in Resonant Reflective Metasurfaces. in IEEE Journal of Selected Topics in Quantum Electronics. 2021;27(1):9130831.
doi:10.1109/JSTQE.2020.3006368 .

Isić, Goran, Zografopoulos, Dimitrios C., Stojanović, Danka, Vasić, Borislav Z., Belić, Milivoj R., "Beam Steering Efficiency in Resonant Reflective Metasurfaces" in IEEE Journal of Selected Topics in Quantum Electronics, 27, no. 1 (2021):9130831,
https://doi.org/10.1109/JSTQE.2020.3006368 . .

TY  - JOUR
AU  - Stojanović, Danka
AU  - Beličev, Petra
AU  - Radovanović, Jelena V.
AU  - Milanović, Vitomir B.
PY  - 2019
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/8542
AB  - In this work, we have systematically studied the impact of geometric parameters on chiral effects which occur in metamaterial made of Ω elements. The analysis of group delays and electric field enhancements indicate stronger interaction between the structure and right circularly polarized waves. Calculations of optical activity and circular dichroism for different values of geometric parameters, allow us to deduce that the thickness of the wire and the gap size have large influence on these effects. On the other hand, the radius of the wire affects mainly the resonant frequency position which enables frequency tunability. The results indicate that multi-functional design of this chiral metamaterial offers great flexibility for various devices: enantiomeric sensors, circular polarizers and light modulators. © 2019 Elsevier B.V.
T2  - Physics Letters A
T1  - Numerical parametric study of chiral effects and group delays in Ω element based terahertz metamaterial
VL  - 383
IS  - 15
SP  - 1816
EP  - 1820
DO  - 10.1016/j.physleta.2019.02.035
ER  - 

@article{
author = "Stojanović, Danka and Beličev, Petra and Radovanović, Jelena V. and Milanović, Vitomir B.",
year = "2019",
abstract = "In this work, we have systematically studied the impact of geometric parameters on chiral effects which occur in metamaterial made of Ω elements. The analysis of group delays and electric field enhancements indicate stronger interaction between the structure and right circularly polarized waves. Calculations of optical activity and circular dichroism for different values of geometric parameters, allow us to deduce that the thickness of the wire and the gap size have large influence on these effects. On the other hand, the radius of the wire affects mainly the resonant frequency position which enables frequency tunability. The results indicate that multi-functional design of this chiral metamaterial offers great flexibility for various devices: enantiomeric sensors, circular polarizers and light modulators. © 2019 Elsevier B.V.",
journal = "Physics Letters A",
title = "Numerical parametric study of chiral effects and group delays in Ω element based terahertz metamaterial",
volume = "383",
number = "15",
pages = "1816-1820",
doi = "10.1016/j.physleta.2019.02.035"
}

Stojanović, D., Beličev, P., Radovanović, J. V.,& Milanović, V. B.. (2019). Numerical parametric study of chiral effects and group delays in Ω element based terahertz metamaterial. in Physics Letters A, 383(15), 1816-1820.
https://doi.org/10.1016/j.physleta.2019.02.035

Stojanović D, Beličev P, Radovanović JV, Milanović VB. Numerical parametric study of chiral effects and group delays in Ω element based terahertz metamaterial. in Physics Letters A. 2019;383(15):1816-1820.
doi:10.1016/j.physleta.2019.02.035 .

Stojanović, Danka, Beličev, Petra, Radovanović, Jelena V., Milanović, Vitomir B., "Numerical parametric study of chiral effects and group delays in Ω element based terahertz metamaterial" in Physics Letters A, 383, no. 15 (2019):1816-1820,
https://doi.org/10.1016/j.physleta.2019.02.035 . .

TY  - CONF
AU  - Stojanović, Danka
PY  - 2019
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/11860
AB  - An object is chiral if it cannot be overlapped with its mirror image. One of the manifestations of chirality in optics are chiral metamaterials, responsible for the appearance of optical activity and circular dichroism. These effects originate from polarization rotation which occurs because waves of the opposite handedness propagate with unequal phases and absorption rates through this kind of material [1]. Circular dichroism has an important role in applications of chiral metamaterials related to manipulation of circularly polarized waves. Nowadays, there is a need for development of devices relevant for terahertz and infrared technologies, in particular for spectroscopy, imaging and communications. Numerous designs of chiral resonant elements have been proposed until now, providing components for terahertz wave modulation, switching and sensing [2-4]. Similarly, chiral structures can enhance infrared signal of chiral molecules which enables detection of enantiomers of these molecules by measuring circular dichroism. In this study, we performed numerical simulations of terahertz wave propagation through chiral metamaterial composed of twisted closed ring resonators [5]. In the absorption spectra, three resonances were distinguished as a result of the existence of electric dipoles and quadrupoles. By this design of resonator, high values of circular dichroism as well as strong local electric field enhancement are obtained. The most significant results are seen at first resonant frequency which appears as a consequence of the gap provided by twisting the ring resonator. Furthermore, we extended our research to infrared range by scaling the chiral resonator dimensions. Values of circular dichroism within this frequency range indicate different performance capabilities when comparing to the terahertz case. In addition, we examined the influence of losses in metal and dielectric on this quantity for both frequency ranges.
PB  - Belgrade : Vinča Institute of Nuclear Sciences, University of Belgrade
C3  - PHOTONICA2019 : 7th International School and Conference on Photonics & Machine Learning with Photonics Symposium : Book of abstracts
T1  - Circular dichroism in twisted resonator based chiral metamaterial
SP  - 35
EP  - 35
UR  - https://hdl.handle.net/21.15107/rcub_vinar_11860
ER  - 

@conference{
author = "Stojanović, Danka",
year = "2019",
abstract = "An object is chiral if it cannot be overlapped with its mirror image. One of the manifestations of chirality in optics are chiral metamaterials, responsible for the appearance of optical activity and circular dichroism. These effects originate from polarization rotation which occurs because waves of the opposite handedness propagate with unequal phases and absorption rates through this kind of material [1]. Circular dichroism has an important role in applications of chiral metamaterials related to manipulation of circularly polarized waves. Nowadays, there is a need for development of devices relevant for terahertz and infrared technologies, in particular for spectroscopy, imaging and communications. Numerous designs of chiral resonant elements have been proposed until now, providing components for terahertz wave modulation, switching and sensing [2-4]. Similarly, chiral structures can enhance infrared signal of chiral molecules which enables detection of enantiomers of these molecules by measuring circular dichroism. In this study, we performed numerical simulations of terahertz wave propagation through chiral metamaterial composed of twisted closed ring resonators [5]. In the absorption spectra, three resonances were distinguished as a result of the existence of electric dipoles and quadrupoles. By this design of resonator, high values of circular dichroism as well as strong local electric field enhancement are obtained. The most significant results are seen at first resonant frequency which appears as a consequence of the gap provided by twisting the ring resonator. Furthermore, we extended our research to infrared range by scaling the chiral resonator dimensions. Values of circular dichroism within this frequency range indicate different performance capabilities when comparing to the terahertz case. In addition, we examined the influence of losses in metal and dielectric on this quantity for both frequency ranges.",
publisher = "Belgrade : Vinča Institute of Nuclear Sciences, University of Belgrade",
journal = "PHOTONICA2019 : 7th International School and Conference on Photonics & Machine Learning with Photonics Symposium : Book of abstracts",
title = "Circular dichroism in twisted resonator based chiral metamaterial",
pages = "35-35",
url = "https://hdl.handle.net/21.15107/rcub_vinar_11860"
}

Stojanović, D.. (2019). Circular dichroism in twisted resonator based chiral metamaterial. in PHOTONICA2019 : 7th International School and Conference on Photonics & Machine Learning with Photonics Symposium : Book of abstracts
Belgrade : Vinča Institute of Nuclear Sciences, University of Belgrade., 35-35.
https://hdl.handle.net/21.15107/rcub_vinar_11860

Stojanović D. Circular dichroism in twisted resonator based chiral metamaterial. in PHOTONICA2019 : 7th International School and Conference on Photonics & Machine Learning with Photonics Symposium : Book of abstracts. 2019;:35-35.
https://hdl.handle.net/21.15107/rcub_vinar_11860 .

Stojanović, Danka, "Circular dichroism in twisted resonator based chiral metamaterial" in PHOTONICA2019 : 7th International School and Conference on Photonics & Machine Learning with Photonics Symposium : Book of abstracts (2019):35-35,
https://hdl.handle.net/21.15107/rcub_vinar_11860 .

TY  - JOUR
AU  - Stojanović, Danka
AU  - Beličev, Petra
AU  - Gligorić, Goran
AU  - Hadžievski, Ljupčo
PY  - 2018
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/1909
AB  - We present a chiral metamaterial (CMM) made of periodically distributed compact elements in a form of twisted closed ring resonators designed to be operational in terahertz (THz) frequency range. We analyze the three observed resonances in the absorption spectra and electric field distribution of linearly polarized incident electromagnetic waves. It has been shown that they arise due to excitation of symmetric and antisymmetric modes and are dependent on the geometry of resonant elements as well as the periodicity of the system. For the case of incident circularly polarized waves, a phenomenon of circular dichroism was observed, and its origin and dependency on the geometrical parameters and metal and dielectric losses was examined. This study indicates that the proposed CMM has a high potential for applications in the design of different THz components.
T2  - Journal of Physics. D: Applied Physics
T1  - Terahertz chiral metamaterial based on twisted closed ring resonators
VL  - 51
IS  - 4
DO  - 10.1088/1361-6463/aaa06d
ER  - 

@article{
author = "Stojanović, Danka and Beličev, Petra and Gligorić, Goran and Hadžievski, Ljupčo",
year = "2018",
abstract = "We present a chiral metamaterial (CMM) made of periodically distributed compact elements in a form of twisted closed ring resonators designed to be operational in terahertz (THz) frequency range. We analyze the three observed resonances in the absorption spectra and electric field distribution of linearly polarized incident electromagnetic waves. It has been shown that they arise due to excitation of symmetric and antisymmetric modes and are dependent on the geometry of resonant elements as well as the periodicity of the system. For the case of incident circularly polarized waves, a phenomenon of circular dichroism was observed, and its origin and dependency on the geometrical parameters and metal and dielectric losses was examined. This study indicates that the proposed CMM has a high potential for applications in the design of different THz components.",
journal = "Journal of Physics. D: Applied Physics",
title = "Terahertz chiral metamaterial based on twisted closed ring resonators",
volume = "51",
number = "4",
doi = "10.1088/1361-6463/aaa06d"
}

Stojanović, D., Beličev, P., Gligorić, G.,& Hadžievski, L.. (2018). Terahertz chiral metamaterial based on twisted closed ring resonators. in Journal of Physics. D: Applied Physics, 51(4).
https://doi.org/10.1088/1361-6463/aaa06d

Stojanović D, Beličev P, Gligorić G, Hadžievski L. Terahertz chiral metamaterial based on twisted closed ring resonators. in Journal of Physics. D: Applied Physics. 2018;51(4).
doi:10.1088/1361-6463/aaa06d .

Stojanović, Danka, Beličev, Petra, Gligorić, Goran, Hadžievski, Ljupčo, "Terahertz chiral metamaterial based on twisted closed ring resonators" in Journal of Physics. D: Applied Physics, 51, no. 4 (2018),
https://doi.org/10.1088/1361-6463/aaa06d . .

TY  - CONF
AU  - Stojanović, Danka B.
AU  - Beličev, Petra
AU  - Gligorić, Goran
AU  - Hadžievski, Ljupčo
PY  - 2017
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/12735
AB  - Chiral metamaterial consists of periodically placed resonant elements exhibiting chiral effects such as circular dichroism and optical activity. They appear due to the coupling of electric and magnetic fields which is result of an interaction of electromagnetic wave and chiral metamaterial. Numerous designs of chiral resonant elements are proposed providing applications for polarization conversion, filtering and absorption in THz frequency range [1, 2]. Here, we analyze propagation of electromagnetic waves through chiral metamaterial composed of twisted closed ring resonators (TCRR). The proposed chiral metamaterial is ultrathin structure which makes this design easy to fabricate and, at the same time, maintains effects which can be observed in conventional chiral 3D metamaterial structures. Dimensions of chiral elements are chosen to provide resonances within THz frequency range. Different geometrical parameters are varied in order to determine their influence on resonant frequency and losses [3]. For our TCRR chiral metamaterial structure, the analysis is made from microscopic as well as from macroscopic point of view. Through numerical simulations, we calculate electromagnetic field distribution, scattering coefficients, absorption and consequently, circular dichroism. Additionally, we examine losses in our chiral structure in terms of radiative and non-radiative ones [4] and explore its influence on the circular dichroism.
PB  - Belgrade : Institute of Physics Belgrade
C3  - PHOTONICA2017 : 6th International School and Conference on Photonics and COST actions: MP1406 and MP1402 : Program and the book of abstracts
T1  - Electromagnetic wave propagation through chiral metamaterials composed of twisted closed ring resonators
SP  - 190
EP  - 190
UR  - https://hdl.handle.net/21.15107/rcub_vinar_12735
ER  - 

@conference{
author = "Stojanović, Danka B. and Beličev, Petra and Gligorić, Goran and Hadžievski, Ljupčo",
year = "2017",
abstract = "Chiral metamaterial consists of periodically placed resonant elements exhibiting chiral effects such as circular dichroism and optical activity. They appear due to the coupling of electric and magnetic fields which is result of an interaction of electromagnetic wave and chiral metamaterial. Numerous designs of chiral resonant elements are proposed providing applications for polarization conversion, filtering and absorption in THz frequency range [1, 2]. Here, we analyze propagation of electromagnetic waves through chiral metamaterial composed of twisted closed ring resonators (TCRR). The proposed chiral metamaterial is ultrathin structure which makes this design easy to fabricate and, at the same time, maintains effects which can be observed in conventional chiral 3D metamaterial structures. Dimensions of chiral elements are chosen to provide resonances within THz frequency range. Different geometrical parameters are varied in order to determine their influence on resonant frequency and losses [3]. For our TCRR chiral metamaterial structure, the analysis is made from microscopic as well as from macroscopic point of view. Through numerical simulations, we calculate electromagnetic field distribution, scattering coefficients, absorption and consequently, circular dichroism. Additionally, we examine losses in our chiral structure in terms of radiative and non-radiative ones [4] and explore its influence on the circular dichroism.",
publisher = "Belgrade : Institute of Physics Belgrade",
journal = "PHOTONICA2017 : 6th International School and Conference on Photonics and COST actions: MP1406 and MP1402 : Program and the book of abstracts",
title = "Electromagnetic wave propagation through chiral metamaterials composed of twisted closed ring resonators",
pages = "190-190",
url = "https://hdl.handle.net/21.15107/rcub_vinar_12735"
}

Stojanović, D. B., Beličev, P., Gligorić, G.,& Hadžievski, L.. (2017). Electromagnetic wave propagation through chiral metamaterials composed of twisted closed ring resonators. in PHOTONICA2017 : 6th International School and Conference on Photonics and COST actions: MP1406 and MP1402 : Program and the book of abstracts
Belgrade : Institute of Physics Belgrade., 190-190.
https://hdl.handle.net/21.15107/rcub_vinar_12735

Stojanović DB, Beličev P, Gligorić G, Hadžievski L. Electromagnetic wave propagation through chiral metamaterials composed of twisted closed ring resonators. in PHOTONICA2017 : 6th International School and Conference on Photonics and COST actions: MP1406 and MP1402 : Program and the book of abstracts. 2017;:190-190.
https://hdl.handle.net/21.15107/rcub_vinar_12735 .

Stojanović, Danka B., Beličev, Petra, Gligorić, Goran, Hadžievski, Ljupčo, "Electromagnetic wave propagation through chiral metamaterials composed of twisted closed ring resonators" in PHOTONICA2017 : 6th International School and Conference on Photonics and COST actions: MP1406 and MP1402 : Program and the book of abstracts (2017):190-190,
https://hdl.handle.net/21.15107/rcub_vinar_12735 .

TY  - CONF
AU  - Stojanović, Danka B.
AU  - Beličev, Petra
AU  - Gligorić, Goran
AU  - Radovanović, Jelena V.
AU  - Milanović, Vitomir B.
AU  - Hadžievski, Ljupčo
PY  - 2017
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/12789
PB  - Belgrade : Institute of physics
C3  - 10th Photonics Workshop : Book of abstracts
T1  - Electromagnetic wave propagation through terahertz chiral metamaterials
SP  - 9
EP  - 9
UR  - https://hdl.handle.net/21.15107/rcub_vinar_12789
ER  - 

@conference{
author = "Stojanović, Danka B. and Beličev, Petra and Gligorić, Goran and Radovanović, Jelena V. and Milanović, Vitomir B. and Hadžievski, Ljupčo",
year = "2017",
publisher = "Belgrade : Institute of physics",
journal = "10th Photonics Workshop : Book of abstracts",
title = "Electromagnetic wave propagation through terahertz chiral metamaterials",
pages = "9-9",
url = "https://hdl.handle.net/21.15107/rcub_vinar_12789"
}

Stojanović, D. B., Beličev, P., Gligorić, G., Radovanović, J. V., Milanović, V. B.,& Hadžievski, L.. (2017). Electromagnetic wave propagation through terahertz chiral metamaterials. in 10th Photonics Workshop : Book of abstracts
Belgrade : Institute of physics., 9-9.
https://hdl.handle.net/21.15107/rcub_vinar_12789

Stojanović DB, Beličev P, Gligorić G, Radovanović JV, Milanović VB, Hadžievski L. Electromagnetic wave propagation through terahertz chiral metamaterials. in 10th Photonics Workshop : Book of abstracts. 2017;:9-9.
https://hdl.handle.net/21.15107/rcub_vinar_12789 .

Stojanović, Danka B., Beličev, Petra, Gligorić, Goran, Radovanović, Jelena V., Milanović, Vitomir B., Hadžievski, Ljupčo, "Electromagnetic wave propagation through terahertz chiral metamaterials" in 10th Photonics Workshop : Book of abstracts (2017):9-9,
https://hdl.handle.net/21.15107/rcub_vinar_12789 .

TY  - JOUR
AU  - Stojanović, Danka
AU  - Radovanović, Jelena V.
AU  - Milanović, Vitomir B.
PY  - 2016
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/1019
AB  - Recently, group delay has been proven as a very convenient tool for control of terahertz electromagnetic signals used for filters, waveguides and polarization components. Here, we investigate the propagation of circularly polarised terahertz pulse via analysis of group delays in X particle chiral metamaterial. When varying the geometry of the X particle chiral metamaterial, significant modification of chiroptical effects- optical activity and circular dichroism can be observed. Through the analysis of group delays in the frequency region between 1 and 3 THz we conclude that the right circularly polarised wave is more sensitive to changes in the geometry than the left circularly polarised wave. This result implies that the right circularly polarised wave is responsible for variation of chiroptical effects in these structures and opens up a possibility for potential applications.
PB  - Springer
T2  - Optical and Quantum Electronics
T1  - Influence of the geometry of terahertz chiral metamaterial on transmission group delays
VL  - 48
IS  - 4
DO  - 10.1007/s11082-016-0533-y
ER  - 

@article{
author = "Stojanović, Danka and Radovanović, Jelena V. and Milanović, Vitomir B.",
year = "2016",
abstract = "Recently, group delay has been proven as a very convenient tool for control of terahertz electromagnetic signals used for filters, waveguides and polarization components. Here, we investigate the propagation of circularly polarised terahertz pulse via analysis of group delays in X particle chiral metamaterial. When varying the geometry of the X particle chiral metamaterial, significant modification of chiroptical effects- optical activity and circular dichroism can be observed. Through the analysis of group delays in the frequency region between 1 and 3 THz we conclude that the right circularly polarised wave is more sensitive to changes in the geometry than the left circularly polarised wave. This result implies that the right circularly polarised wave is responsible for variation of chiroptical effects in these structures and opens up a possibility for potential applications.",
publisher = "Springer",
journal = "Optical and Quantum Electronics",
title = "Influence of the geometry of terahertz chiral metamaterial on transmission group delays",
volume = "48",
number = "4",
doi = "10.1007/s11082-016-0533-y"
}

Stojanović, D., Radovanović, J. V.,& Milanović, V. B.. (2016). Influence of the geometry of terahertz chiral metamaterial on transmission group delays. in Optical and Quantum Electronics
Springer., 48(4).
https://doi.org/10.1007/s11082-016-0533-y

Stojanović D, Radovanović JV, Milanović VB. Influence of the geometry of terahertz chiral metamaterial on transmission group delays. in Optical and Quantum Electronics. 2016;48(4).
doi:10.1007/s11082-016-0533-y .

Stojanović, Danka, Radovanović, Jelena V., Milanović, Vitomir B., "Influence of the geometry of terahertz chiral metamaterial on transmission group delays" in Optical and Quantum Electronics, 48, no. 4 (2016),
https://doi.org/10.1007/s11082-016-0533-y . .

TY  - JOUR
AU  - Stojanović, Danka
AU  - Radovanović, Jelena V.
AU  - Milanović, Vitomir B.
PY  - 2016
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/1215
AB  - We investigate the propagation of circularly polarized electromagnetic waves through a free-standing Omega particle chiral metamaterial slab and study the associated delay times: dwell time and group delay. Through this analysis, we observe different interactions of right- and left-circularly polarized waves in the terahertz frequency range (1-2.5 THz) with the resonant elements. As a consequence, the resonant-frequency group delay and dwell time of the right-circularly polarized wave are one or more orders of magnitude longer than those of the left. In addition, we compare the delay times obtained from rigorous numerical simulations with those calculated using the retrieved effective parameters. We find that the dwell time cannot be evaluated correctly from the effective medium approximation, while no such problems exist in the case of group delay.
T2  - Physical Review A
T1  - Delay times in a terahertz chiral metamaterial slab
VL  - 94
IS  - 2
DO  - 10.1103/PhysRevA.94.023848
ER  - 

@article{
author = "Stojanović, Danka and Radovanović, Jelena V. and Milanović, Vitomir B.",
year = "2016",
abstract = "We investigate the propagation of circularly polarized electromagnetic waves through a free-standing Omega particle chiral metamaterial slab and study the associated delay times: dwell time and group delay. Through this analysis, we observe different interactions of right- and left-circularly polarized waves in the terahertz frequency range (1-2.5 THz) with the resonant elements. As a consequence, the resonant-frequency group delay and dwell time of the right-circularly polarized wave are one or more orders of magnitude longer than those of the left. In addition, we compare the delay times obtained from rigorous numerical simulations with those calculated using the retrieved effective parameters. We find that the dwell time cannot be evaluated correctly from the effective medium approximation, while no such problems exist in the case of group delay.",
journal = "Physical Review A",
title = "Delay times in a terahertz chiral metamaterial slab",
volume = "94",
number = "2",
doi = "10.1103/PhysRevA.94.023848"
}

Stojanović, D., Radovanović, J. V.,& Milanović, V. B.. (2016). Delay times in a terahertz chiral metamaterial slab. in Physical Review A, 94(2).
https://doi.org/10.1103/PhysRevA.94.023848

Stojanović D, Radovanović JV, Milanović VB. Delay times in a terahertz chiral metamaterial slab. in Physical Review A. 2016;94(2).
doi:10.1103/PhysRevA.94.023848 .

Stojanović, Danka, Radovanović, Jelena V., Milanović, Vitomir B., "Delay times in a terahertz chiral metamaterial slab" in Physical Review A, 94, no. 2 (2016),
https://doi.org/10.1103/PhysRevA.94.023848 . .

TY  - CONF
AU  - Stojanović, Danka
AU  - Chiappini, A.
AU  - Korićanac, Goran
AU  - Nenadović, Miloš
AU  - Ferrari, M.
AU  - Rakočević, Zlatko
PY  - 2015
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/12013
AB  - The great potential of self-assembled colloidal structures in several technological areas of modern photonics derives from the low cost and relative simplicity with which they are fabricated. The optical properties of this kind of medium are not only determined by the response of its isolated constituents but also by their spatial arrangement. When polystyrene spheres self-assemble in a periodic fashion, the spatially ordered variation of the dielectric function gives rise to photonic bands and thus the colloidal structure becomes a photonic crystal [1,2]. In this study, colloidal thin films were prepared by the spin-coating [3] and vertical deposition method [4]. By varying the spinning velocity, acceleration and duration of rotation, we obtained different number of colloidal crystal layers. Also, we have prepared opals (multilayer films) with the vertical deposition technique and compared the obtained structures with those obtained by the spin-coating method. In both cases, the thin films were fabricated by depositing colloidal dispersions of 300 nm polystyrene spheres onto microscope glass slide substrates. The morphology of samples was studied by atomic force microscopy, while their optical properties were investigated by spectroscopic ellipsometry and UV-VIS-IR spectrophotometry. An appropriate model has been developed for the determination of the optical properties of the colloidal films by ellipsometry. In order to validate the model applied, the parameters obtained have been compared with those determined by means of transmittance measurements. From transmittance measurements, in the case of monolayer films, diffraction peak in the visible range was observed. On the other side, in the case of opal has been verified the presence of a photonic band gap which should be attributed to Bragg diffraction [5].
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  - Assessment of structural and optical properties of self-assembled photonic structures
SP  - 189
EP  - 190
UR  - https://hdl.handle.net/21.15107/rcub_vinar_12013
ER  - 

@conference{
author = "Stojanović, Danka and Chiappini, A. and Korićanac, Goran and Nenadović, Miloš and Ferrari, M. and Rakočević, Zlatko",
year = "2015",
abstract = "The great potential of self-assembled colloidal structures in several technological areas of modern photonics derives from the low cost and relative simplicity with which they are fabricated. The optical properties of this kind of medium are not only determined by the response of its isolated constituents but also by their spatial arrangement. When polystyrene spheres self-assemble in a periodic fashion, the spatially ordered variation of the dielectric function gives rise to photonic bands and thus the colloidal structure becomes a photonic crystal [1,2]. In this study, colloidal thin films were prepared by the spin-coating [3] and vertical deposition method [4]. By varying the spinning velocity, acceleration and duration of rotation, we obtained different number of colloidal crystal layers. Also, we have prepared opals (multilayer films) with the vertical deposition technique and compared the obtained structures with those obtained by the spin-coating method. In both cases, the thin films were fabricated by depositing colloidal dispersions of 300 nm polystyrene spheres onto microscope glass slide substrates. The morphology of samples was studied by atomic force microscopy, while their optical properties were investigated by spectroscopic ellipsometry and UV-VIS-IR spectrophotometry. An appropriate model has been developed for the determination of the optical properties of the colloidal films by ellipsometry. In order to validate the model applied, the parameters obtained have been compared with those determined by means of transmittance measurements. From transmittance measurements, in the case of monolayer films, diffraction peak in the visible range was observed. On the other side, in the case of opal has been verified the presence of a photonic band gap which should be attributed to Bragg diffraction [5].",
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 = "Assessment of structural and optical properties of self-assembled photonic structures",
pages = "189-190",
url = "https://hdl.handle.net/21.15107/rcub_vinar_12013"
}

Stojanović, D., Chiappini, A., Korićanac, G., Nenadović, M., Ferrari, M.,& Rakočević, Z.. (2015). Assessment of structural and optical properties of self-assembled photonic structures. 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., 189-190.
https://hdl.handle.net/21.15107/rcub_vinar_12013

Stojanović D, Chiappini A, Korićanac G, Nenadović M, Ferrari M, Rakočević Z. Assessment of structural and optical properties of self-assembled photonic structures. 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;:189-190.
https://hdl.handle.net/21.15107/rcub_vinar_12013 .

Stojanović, Danka, Chiappini, A., Korićanac, Goran, Nenadović, Miloš, Ferrari, M., Rakočević, Zlatko, "Assessment of structural and optical properties of self-assembled photonic structures" 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):189-190,
https://hdl.handle.net/21.15107/rcub_vinar_12013 .

TY  - JOUR
AU  - Stojanović, Danka
AU  - Matkovic, A.
AU  - Askrabic, S.
AU  - Beltaos, A.
AU  - Ralević, Uroš
AU  - Jovanović, Đorđe
AU  - Bajuk-Bogdanović, Danica V.
AU  - Holclajtner-Antunović, Ivanka D.
AU  - Gajic, R.
PY  - 2013
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/7017
AB  - In this study, graphene samples prepared by mechanical exfoliation were examined by Raman spectroscopy. The Au electrical contacts, fabricated using photolithography, allowed the application of a gate voltage between graphene and the Si substrate. In the Raman spectra of the sample, we observed shifts of position, changes of intensity and the width variations of the G and 2D peaks with the change of the gate voltage. Spatial Raman mapping of the samples was performed showing variations in intensities of the Raman peaks in different flake regions.
T2  - Physica Scripta
T1  - Raman spectroscopy of graphene: doping and mapping
VL  - T157
DO  - 10.1088/0031-8949/2013/T157/014010
ER  - 

@article{
author = "Stojanović, Danka and Matkovic, A. and Askrabic, S. and Beltaos, A. and Ralević, Uroš and Jovanović, Đorđe and Bajuk-Bogdanović, Danica V. and Holclajtner-Antunović, Ivanka D. and Gajic, R.",
year = "2013",
abstract = "In this study, graphene samples prepared by mechanical exfoliation were examined by Raman spectroscopy. The Au electrical contacts, fabricated using photolithography, allowed the application of a gate voltage between graphene and the Si substrate. In the Raman spectra of the sample, we observed shifts of position, changes of intensity and the width variations of the G and 2D peaks with the change of the gate voltage. Spatial Raman mapping of the samples was performed showing variations in intensities of the Raman peaks in different flake regions.",
journal = "Physica Scripta",
title = "Raman spectroscopy of graphene: doping and mapping",
volume = "T157",
doi = "10.1088/0031-8949/2013/T157/014010"
}

Stojanović, D., Matkovic, A., Askrabic, S., Beltaos, A., Ralević, U., Jovanović, Đ., Bajuk-Bogdanović, D. V., Holclajtner-Antunović, I. D.,& Gajic, R.. (2013). Raman spectroscopy of graphene: doping and mapping. in Physica Scripta, T157.
https://doi.org/10.1088/0031-8949/2013/T157/014010

Stojanović D, Matkovic A, Askrabic S, Beltaos A, Ralević U, Jovanović Đ, Bajuk-Bogdanović DV, Holclajtner-Antunović ID, Gajic R. Raman spectroscopy of graphene: doping and mapping. in Physica Scripta. 2013;T157.
doi:10.1088/0031-8949/2013/T157/014010 .

Stojanović, Danka, Matkovic, A., Askrabic, S., Beltaos, A., Ralević, Uroš, Jovanović, Đorđe, Bajuk-Bogdanović, Danica V., Holclajtner-Antunović, Ivanka D., Gajic, R., "Raman spectroscopy of graphene: doping and mapping" in Physica Scripta, T157 (2013),
https://doi.org/10.1088/0031-8949/2013/T157/014010 . .

TY  - JOUR
AU  - Musbah, S. S.
AU  - Radojević, Vesna
AU  - Radović, Ivana M.
AU  - Uskokovic, P. S.
AU  - Stojanović, Danka
AU  - Dramićanin, Miroslav
AU  - Aleksić, R.
PY  - 2012
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/5103
AB  - This study reports research related to different preparation methods and characterization of polymer nanocomposites for optical applications. The Eu-ion doped Gd2O3 nanophosphor powder with different nanoparticle content was embedded in the matrix of PMMA. Preparation was carried out by mixing molding (bulk), electrospinning (nanofibers) and solution casting (thin films) with neat particles and particles coated with AMEO silane. Among the pros and cons for proposed methods, the mixing molding enables to avoid solvent use while the best deagglomeration and nanoparticle distribution is gained using the electrospinning method. The results of dynamic mechanical analysis (DMA) and nanoindentation revealed that the storage modulus of the composites was higher than that of pure PMMA and increased with nanophosphor content. Surface modification of particles improved the mechanical properties of nanocomposites.
T2  - Journal of mining and metallurgy, Section B: Metallurgy
T1  - Preparation, Characterization and Mechanical Properties of Rare-Earth-Based Nanocomposites
VL  - 48
IS  - 2
SP  - 309
EP  - 318
DO  - 10.2298/JMMB120508030M
ER  - 

@article{
author = "Musbah, S. S. and Radojević, Vesna and Radović, Ivana M. and Uskokovic, P. S. and Stojanović, Danka and Dramićanin, Miroslav and Aleksić, R.",
year = "2012",
abstract = "This study reports research related to different preparation methods and characterization of polymer nanocomposites for optical applications. The Eu-ion doped Gd2O3 nanophosphor powder with different nanoparticle content was embedded in the matrix of PMMA. Preparation was carried out by mixing molding (bulk), electrospinning (nanofibers) and solution casting (thin films) with neat particles and particles coated with AMEO silane. Among the pros and cons for proposed methods, the mixing molding enables to avoid solvent use while the best deagglomeration and nanoparticle distribution is gained using the electrospinning method. The results of dynamic mechanical analysis (DMA) and nanoindentation revealed that the storage modulus of the composites was higher than that of pure PMMA and increased with nanophosphor content. Surface modification of particles improved the mechanical properties of nanocomposites.",
journal = "Journal of mining and metallurgy, Section B: Metallurgy",
title = "Preparation, Characterization and Mechanical Properties of Rare-Earth-Based Nanocomposites",
volume = "48",
number = "2",
pages = "309-318",
doi = "10.2298/JMMB120508030M"
}

Musbah, S. S., Radojević, V., Radović, I. M., Uskokovic, P. S., Stojanović, D., Dramićanin, M.,& Aleksić, R.. (2012). Preparation, Characterization and Mechanical Properties of Rare-Earth-Based Nanocomposites. in Journal of mining and metallurgy, Section B: Metallurgy, 48(2), 309-318.
https://doi.org/10.2298/JMMB120508030M

Musbah SS, Radojević V, Radović IM, Uskokovic PS, Stojanović D, Dramićanin M, Aleksić R. Preparation, Characterization and Mechanical Properties of Rare-Earth-Based Nanocomposites. in Journal of mining and metallurgy, Section B: Metallurgy. 2012;48(2):309-318.
doi:10.2298/JMMB120508030M .

Musbah, S. S., Radojević, Vesna, Radović, Ivana M., Uskokovic, P. S., Stojanović, Danka, Dramićanin, Miroslav, Aleksić, R., "Preparation, Characterization and Mechanical Properties of Rare-Earth-Based Nanocomposites" in Journal of mining and metallurgy, Section B: Metallurgy, 48, no. 2 (2012):309-318,
https://doi.org/10.2298/JMMB120508030M . .