Elena Romanova | Saratov State University (original) (raw)

Papers by Elena Romanova

Research paper thumbnail of Mode Propagation along the Multilayered Optical Fibre with Kerr Like Non-Linearity

Research paper thumbnail of Wave propagation through all-dielectric multilayered optical fiber

2000 2nd International Conference on Transparent Optical Networks. Conference Proceedings (Cat. No.00EX408), 2000

The optical fibers widely used in telecommunications, sensor technology and medicine usually oper... more The optical fibers widely used in telecommunications, sensor technology and medicine usually operate by the principle of total internal reflection, with a core of higher refractive index than that of the cladding material. Meanwhile, the emergence of dielectric structures with periodic variation in the refractive index has opened up new possibilities for controlling light propagation. One example of such a structure is the so-called photonic crystal fiber with a pure silica core and microstructured cladding [ 13. Such fibers can be made so as to support a single mode or several modes and designed to support only a single guided mode for all wavelengths independent of the fiber size.

Research paper thumbnail of Modelling of a High - Intensity Pulse Propagation in All - Dielectric Multilayered Fibres by the Time - Domain Finite - Difference Beam Propagation Method

Research paper thumbnail of Interplay of non-linearity and dispersion in chalcogenide glass

2010 10th International Conference on Laser and Fiber-Optical Networks Modeling, 2010

ABSTRACT

Research paper thumbnail of Dispersion Management in Chip-Scale Periodic Structures Fabricated in Chalcogenide Glass for High-Intensity Pulse Shaping

Research paper thumbnail of Non-linear optical response of bulk chalcogenide glasses near the fundamental absorption band edge

Journal of Physics Conference Series

Magnitudes of the non-linear coefficients of absorption and refraction have been evaluated near t... more Magnitudes of the non-linear coefficients of absorption and refraction have been evaluated near the bandgap wavelengths of chalcogenide glasses of the system AsS -Se by using the interferometric pump-probe method and are compared with literature data. Photo-excited plasma dynamics and long-time scale variation of the dielectric constant have been studied by comparison with the results of numerical modelling of the behaviour of the glasses when heated by the ultra-short laser pulses. 1. Introduction As other amorphous semiconductors, chalcogenide glasses have a disordered lattice and localised states of electrons in their bandgaps. Due to these specific structural and electronic properties, fundamental absorption band edge of amorphous semiconductors is not sharp. It has a spectral range of exponential decay of the single-photon absorption coefficient α that is usually referred to as the Urbach tail. Chalcogenide glasses have also weak absorption tails with α < 1 cm-1 [1]. Using o...

Research paper thumbnail of Specific features of linear and nonlinear optical responses of chalcogenide glasses in the As-S-Se and As-Se-Te systems

Optics and Spectroscopy

Transmission and reflection spectra of samples of chalcogenide glasses in the As–S–Se and As–Se–T... more Transmission and reflection spectra of samples of chalcogenide glasses in the As–S–Se and As–Se–Te systems have been measured in the wavelength range of 0.4–2.5 μm. Spectral dependences of the single photon absorption coefficient and refractive index are obtained, the parameters characterizing the fundamental absorption edge are determined, and the Kerr constant in the low frequency limit is calculated. Based on the obtained results and the data in the literature, dispersion curves are plotted for the Kerr constants of As2S3 and As2Se3 glasses near the absorption edge.

Research paper thumbnail of Nonlinear optical properties of amorphous semiconductors

2012 International Conference on Mathematical Methods in Electromagnetic Theory, 2012

ABSTRACT Theoretical and experimental approaches to study dispersion of the nonlinear coefficient... more ABSTRACT Theoretical and experimental approaches to study dispersion of the nonlinear coefficients of refraction and absorption in amorphous semiconductors are overviewed. Nonlinear properties of the chalcogenide glasses over a wide spectral range are studied in various models and discussed.

Research paper thumbnail of Third-order non-linear optical response in chalcogenide glasses: Measurement and evaluation

2013 15th International Conference on Transparent Optical Networks (ICTON), 2013

ABSTRACT

Research paper thumbnail of Processing of chalcogenide glass by the femtosecond laser pulses for achieving highly non-linear photonic structures

CLEO/Europe - EQEC 2009 - European Conference on Lasers and Electro-Optics and the European Quantum Electronics Conference, 2009

... 0.0 -~---r-~--I 0.20 0.22 0.24 0.26 (b) z, mm (zr) 0.9GaJ ... Elena Romanova&#x27;, Andre... more ... 0.0 -~---r-~--I 0.20 0.22 0.24 0.26 (b) z, mm (zr) 0.9GaJ ... Elena Romanova&#x27;, Andrey Konyukhov&#x27;, Sergey Muraviov&#x27;, Alexey Andrianov&#x27;, Trevor Benson&quot;, Angela Seddon&quot;, David Furniss&#x27; 1. Saratov State University, Astrakhanskaya 83, Sarat ov, 410012 , Russia 2. Institute ofApplied ...

Research paper thumbnail of Dispersion tailoring in chalcogenide slot waveguides, slot arrays and bandgap structures

2012 14th International Conference on Transparent Optical Networks (ICTON), 2012

ABSTRACT

Research paper thumbnail of Glass photonic crystals: fabrication, optical properties and applications

LEOS 2001. 14th Annual Meeting of the IEEE Lasers and Electro-Optics Society (Cat. No.01CH37242), 2001

Research paper thumbnail of Computer modeling of the nonlinear absorption of an ultra-fast laser beam focused into a glass sample

2012 International Conference on Mathematical Methods in Electromagnetic Theory, 2012

ABSTRACT

Research paper thumbnail of Thermal regimes in optical glass modification by the ultra-short laser pulses

2012 14th International Conference on Transparent Optical Networks (ICTON), 2012

ABSTRACT

Research paper thumbnail of Nonlinear absorption of ultrashort pulses in self-focusing glass medium at different wavelengths

2011 13th International Conference on Transparent Optical Networks, 2011

Energy of an ultrashort pulse absorbed in a highly nonlinear optical glass is evaluated within an... more Energy of an ultrashort pulse absorbed in a highly nonlinear optical glass is evaluated within an analytical model based on approximate theoretical approach. Self-focusing of a Gaussian beam and its focusing by a lens are taken into account. Dispersion of nonlinear coefficients of refraction and absorption is taken into account.

Research paper thumbnail of Design of Non-Linear Guiding Structures for Processing of the Ultra-Short Laser Pulses

Research paper thumbnail of Chalcogenide waveguides as a base for engineering broadband light sources in the mid-infrared

2011 13th International Conference on Transparent Optical Networks, 2011

Chalcogenide glasses are important for applications in the mid-infrared (IR) spectral range becau... more Chalcogenide glasses are important for applications in the mid-infrared (IR) spectral range because of their good mid-IR transparency and their high non-linear refractive indices. Our research is focused on creation of mid-IR supercontinuum sources. Numerical modelling of the ultra-short pulse propagation in various kinds of chalcogenide waveguides is complemented by experimental measurement of pulse spectrum broadening in some particular structures.

Research paper thumbnail of Experimental studies of non-linear properties of chalcogenide glasses

2009 11th International Conference on Transparent Optical Networks, 2009

ABSTRACT This paper is focused on discussion of various experimental techniques that are used to ... more ABSTRACT This paper is focused on discussion of various experimental techniques that are used to measure non-linear coefficients of refraction and absorption in optical glasses. These techniques are usually classified as z-scan and pump-probe like methods. Measurements ...

Research paper thumbnail of Spectral dependence of all-solid photonic bandgap fiber transmittance

2013 International Conference on Advanced Optoelectronics and Lasers (CAOL 2013), 2013

ABSTRACT The results of the numerical modeling of the transmittance of an all-solid photonic band... more ABSTRACT The results of the numerical modeling of the transmittance of an all-solid photonic band gap fiber are presented. For the modeling, a vectorial “wide-angle” Fourier transform based beam propagation method is applied. The actual fiber structure, having morphological deformations of a hexagonal lattice, is considered. The coexistence of high-order total internal reflection modes of high-index rods and the fundamental photonic band gap mode is demonstrated.

Research paper thumbnail of Dispersion of linear and nonlinear refractive index in chalcogenide glass

International Conference on Transparent Optical Networks, 2012

ABSTRACT Fundamental mechanisms of the intensity-dependent refractivity in optical glasses have b... more ABSTRACT Fundamental mechanisms of the intensity-dependent refractivity in optical glasses have been less understood than those in two-level atoms and crystalline semiconductors. In the work, the concept based on the strong dependence of nonlinear refractive index on the bandgap energy is developed. Spectral dependence of the nonlinear refractive index near the bandgap frequency in chalcogenide glasses is considered and compared with direct- and indirect gap crystalline semiconductors.

Research paper thumbnail of Mode Propagation along the Multilayered Optical Fibre with Kerr Like Non-Linearity

Research paper thumbnail of Wave propagation through all-dielectric multilayered optical fiber

2000 2nd International Conference on Transparent Optical Networks. Conference Proceedings (Cat. No.00EX408), 2000

The optical fibers widely used in telecommunications, sensor technology and medicine usually oper... more The optical fibers widely used in telecommunications, sensor technology and medicine usually operate by the principle of total internal reflection, with a core of higher refractive index than that of the cladding material. Meanwhile, the emergence of dielectric structures with periodic variation in the refractive index has opened up new possibilities for controlling light propagation. One example of such a structure is the so-called photonic crystal fiber with a pure silica core and microstructured cladding [ 13. Such fibers can be made so as to support a single mode or several modes and designed to support only a single guided mode for all wavelengths independent of the fiber size.

Research paper thumbnail of Modelling of a High - Intensity Pulse Propagation in All - Dielectric Multilayered Fibres by the Time - Domain Finite - Difference Beam Propagation Method

Research paper thumbnail of Interplay of non-linearity and dispersion in chalcogenide glass

2010 10th International Conference on Laser and Fiber-Optical Networks Modeling, 2010

ABSTRACT

Research paper thumbnail of Dispersion Management in Chip-Scale Periodic Structures Fabricated in Chalcogenide Glass for High-Intensity Pulse Shaping

Research paper thumbnail of Non-linear optical response of bulk chalcogenide glasses near the fundamental absorption band edge

Journal of Physics Conference Series

Magnitudes of the non-linear coefficients of absorption and refraction have been evaluated near t... more Magnitudes of the non-linear coefficients of absorption and refraction have been evaluated near the bandgap wavelengths of chalcogenide glasses of the system AsS -Se by using the interferometric pump-probe method and are compared with literature data. Photo-excited plasma dynamics and long-time scale variation of the dielectric constant have been studied by comparison with the results of numerical modelling of the behaviour of the glasses when heated by the ultra-short laser pulses. 1. Introduction As other amorphous semiconductors, chalcogenide glasses have a disordered lattice and localised states of electrons in their bandgaps. Due to these specific structural and electronic properties, fundamental absorption band edge of amorphous semiconductors is not sharp. It has a spectral range of exponential decay of the single-photon absorption coefficient α that is usually referred to as the Urbach tail. Chalcogenide glasses have also weak absorption tails with α < 1 cm-1 [1]. Using o...

Research paper thumbnail of Specific features of linear and nonlinear optical responses of chalcogenide glasses in the As-S-Se and As-Se-Te systems

Optics and Spectroscopy

Transmission and reflection spectra of samples of chalcogenide glasses in the As–S–Se and As–Se–T... more Transmission and reflection spectra of samples of chalcogenide glasses in the As–S–Se and As–Se–Te systems have been measured in the wavelength range of 0.4–2.5 μm. Spectral dependences of the single photon absorption coefficient and refractive index are obtained, the parameters characterizing the fundamental absorption edge are determined, and the Kerr constant in the low frequency limit is calculated. Based on the obtained results and the data in the literature, dispersion curves are plotted for the Kerr constants of As2S3 and As2Se3 glasses near the absorption edge.

Research paper thumbnail of Nonlinear optical properties of amorphous semiconductors

2012 International Conference on Mathematical Methods in Electromagnetic Theory, 2012

ABSTRACT Theoretical and experimental approaches to study dispersion of the nonlinear coefficient... more ABSTRACT Theoretical and experimental approaches to study dispersion of the nonlinear coefficients of refraction and absorption in amorphous semiconductors are overviewed. Nonlinear properties of the chalcogenide glasses over a wide spectral range are studied in various models and discussed.

Research paper thumbnail of Third-order non-linear optical response in chalcogenide glasses: Measurement and evaluation

2013 15th International Conference on Transparent Optical Networks (ICTON), 2013

ABSTRACT

Research paper thumbnail of Processing of chalcogenide glass by the femtosecond laser pulses for achieving highly non-linear photonic structures

CLEO/Europe - EQEC 2009 - European Conference on Lasers and Electro-Optics and the European Quantum Electronics Conference, 2009

... 0.0 -~---r-~--I 0.20 0.22 0.24 0.26 (b) z, mm (zr) 0.9GaJ ... Elena Romanova&#x27;, Andre... more ... 0.0 -~---r-~--I 0.20 0.22 0.24 0.26 (b) z, mm (zr) 0.9GaJ ... Elena Romanova&#x27;, Andrey Konyukhov&#x27;, Sergey Muraviov&#x27;, Alexey Andrianov&#x27;, Trevor Benson&quot;, Angela Seddon&quot;, David Furniss&#x27; 1. Saratov State University, Astrakhanskaya 83, Sarat ov, 410012 , Russia 2. Institute ofApplied ...

Research paper thumbnail of Dispersion tailoring in chalcogenide slot waveguides, slot arrays and bandgap structures

2012 14th International Conference on Transparent Optical Networks (ICTON), 2012

ABSTRACT

Research paper thumbnail of Glass photonic crystals: fabrication, optical properties and applications

LEOS 2001. 14th Annual Meeting of the IEEE Lasers and Electro-Optics Society (Cat. No.01CH37242), 2001

Research paper thumbnail of Computer modeling of the nonlinear absorption of an ultra-fast laser beam focused into a glass sample

2012 International Conference on Mathematical Methods in Electromagnetic Theory, 2012

ABSTRACT

Research paper thumbnail of Thermal regimes in optical glass modification by the ultra-short laser pulses

2012 14th International Conference on Transparent Optical Networks (ICTON), 2012

ABSTRACT

Research paper thumbnail of Nonlinear absorption of ultrashort pulses in self-focusing glass medium at different wavelengths

2011 13th International Conference on Transparent Optical Networks, 2011

Energy of an ultrashort pulse absorbed in a highly nonlinear optical glass is evaluated within an... more Energy of an ultrashort pulse absorbed in a highly nonlinear optical glass is evaluated within an analytical model based on approximate theoretical approach. Self-focusing of a Gaussian beam and its focusing by a lens are taken into account. Dispersion of nonlinear coefficients of refraction and absorption is taken into account.

Research paper thumbnail of Design of Non-Linear Guiding Structures for Processing of the Ultra-Short Laser Pulses

Research paper thumbnail of Chalcogenide waveguides as a base for engineering broadband light sources in the mid-infrared

2011 13th International Conference on Transparent Optical Networks, 2011

Chalcogenide glasses are important for applications in the mid-infrared (IR) spectral range becau... more Chalcogenide glasses are important for applications in the mid-infrared (IR) spectral range because of their good mid-IR transparency and their high non-linear refractive indices. Our research is focused on creation of mid-IR supercontinuum sources. Numerical modelling of the ultra-short pulse propagation in various kinds of chalcogenide waveguides is complemented by experimental measurement of pulse spectrum broadening in some particular structures.

Research paper thumbnail of Experimental studies of non-linear properties of chalcogenide glasses

2009 11th International Conference on Transparent Optical Networks, 2009

ABSTRACT This paper is focused on discussion of various experimental techniques that are used to ... more ABSTRACT This paper is focused on discussion of various experimental techniques that are used to measure non-linear coefficients of refraction and absorption in optical glasses. These techniques are usually classified as z-scan and pump-probe like methods. Measurements ...

Research paper thumbnail of Spectral dependence of all-solid photonic bandgap fiber transmittance

2013 International Conference on Advanced Optoelectronics and Lasers (CAOL 2013), 2013

ABSTRACT The results of the numerical modeling of the transmittance of an all-solid photonic band... more ABSTRACT The results of the numerical modeling of the transmittance of an all-solid photonic band gap fiber are presented. For the modeling, a vectorial “wide-angle” Fourier transform based beam propagation method is applied. The actual fiber structure, having morphological deformations of a hexagonal lattice, is considered. The coexistence of high-order total internal reflection modes of high-index rods and the fundamental photonic band gap mode is demonstrated.

Research paper thumbnail of Dispersion of linear and nonlinear refractive index in chalcogenide glass

International Conference on Transparent Optical Networks, 2012

ABSTRACT Fundamental mechanisms of the intensity-dependent refractivity in optical glasses have b... more ABSTRACT Fundamental mechanisms of the intensity-dependent refractivity in optical glasses have been less understood than those in two-level atoms and crystalline semiconductors. In the work, the concept based on the strong dependence of nonlinear refractive index on the bandgap energy is developed. Spectral dependence of the nonlinear refractive index near the bandgap frequency in chalcogenide glasses is considered and compared with direct- and indirect gap crystalline semiconductors.