V. Bushuev - Academia.edu (original) (raw)

Papers by V. Bushuev

Research paper thumbnail of Diffraction-induced laser pulse splitting in a linear photonic crystal

Physical Review A, 2009

Temporal Bragg-diffraction-induced laser-pulse splitting into two pulses propagating with differe... more Temporal Bragg-diffraction-induced laser-pulse splitting into two pulses propagating with different group velocities is observed in multilayered linear photonic crystals (PCs). This phenomenon originates from spatially inhomogeneous light localization within the PCs at the Laue scheme of the dynamical Bragg diffraction. In a homogeneous medium at the PC output each pulse is spatially separated into two pulses, propagating in the transmission and diffraction directions, respectively. The experiments are carried out for a one-dimensional porous silicon-based PC consisting of 375 spatial periods of 800 nm thickness using a femtosecond Ti:sapphire laser as a probe. A linear dependence of the time splitting of each pair of transmitted and diffractively reflected pulses on the crystal thickness is demonstrated and is supported by theoretical estimations.

Research paper thumbnail of <title>Temporal and coherence properties of hard x-ray FEL radiation following Bragg diffraction by crystals</title>

Advances in Computational Methods for X-Ray Optics II, 2011

ABSTRACT

Research paper thumbnail of Diffraction-induced spatially confined laser pulse splitting in photonic crystals

Bulletin of the Russian Academy of Sciences: Physics, 2010

It is shown theoretically that the effect of diffraction-induced optical pulse splitting in a lin... more It is shown theoretically that the effect of diffraction-induced optical pulse splitting in a linear photonic crystal under the conditions of the Laue transmission geometric scheme of Bragg diffraction can be realized for a spatially confined laser pulse in a hundred-period multilayer structure.

Research paper thumbnail of Dielectric permittivity in the x-ray region

Soviet Physics Uspekhi, 1978

Research paper thumbnail of Inelastic scattering of x-ray and synchrotron radiation in crystals, coherent effects in inelastic scattering

Soviet Physics Uspekhi, 1977

Research paper thumbnail of X-ray lasers

Soviet Physics Uspekhi, 1975

Research paper thumbnail of Observation of the temporal Bragg-diffraction-induced laser-pulse splitting in a linear photonic crystal

Research paper thumbnail of Amplification of the generation of the sum-frequency signal in multilayer periodic structures at the edges of the Bragg band gap

Journal of Experimental and Theoretical Physics Letters, 1999

Research paper thumbnail of Enhancement of sum frequency generation near the photonic band gap edge under the quasiphase matching conditions

Physical Review E, 2001

We analyze theoretically and study experimentally the mechanisms of enhancement of the sum freque... more We analyze theoretically and study experimentally the mechanisms of enhancement of the sum frequency and second harmonic generation in a finite one-dimensional photonic band gap structure with second order nonlinearity under Bragg diffraction conditions. It is shown that, near the photonic band gap edge, the efficiency of conversion in sum frequency and second harmonic generation processes can be significantly enhanced if two conditions are fulfilled simultaneously: grating assisted phase matching, or quasiphase matching, and an increase of the electromagnetic field density at the fundamental frequencies near the photonic band edges. The role of each mechanism is discussed.

Research paper thumbnail of Observation of optical second-harmonic generation in porous-silicon-based photonic crystals in the Laue diffraction scheme

Research paper thumbnail of Polarization and nonlinear effects in diffraction-induced laser pulse splitting in one-dimensional photonic crystals

2013 Conference on Lasers & Electro-Optics Europe & International Quantum Electronics Conference CLEO EUROPE/IQEC, 2013

ABSTRACT In this paper, the polarization effects in diffraction-induced pulse spliiting (DIPS) ph... more ABSTRACT In this paper, the polarization effects in diffraction-induced pulse spliiting (DIPS) phenomenon in porous-quartz based 1D photonic crystal (PC) are studied both experimentally and theoretically. The PC was formed with the thickness of each layer of 390 nm and with the period of 780 nm. We made the PC composed of 375 layers, so that the total PC thickness a = 300 μm was large enough for the performance of the experiments in the Laue geometry. The 110 fs light pulses at the wavelength of 800 nm generated by a Ti-sapphire laser were used. The paper demonstrates that the difference in the group velocity of the Borrmann and anti-Borrmann modes is substantially different for the p- and s-polarized pulsed radiation due to a large lattice-induced dispersion in a PC. This leads to a significant change in the value of the splitting time t12 for p- and s-polarized laser pulses propagating within a PC and, in general, in the number of the outgoing pulses as well. After passing a PC the number of outgoing pulses can be varied from two up to four in both transmission (T) and diffractive reflection (R) directions, depending on the polarization of the incident radiation and the parameters of a PC. It is shown theoretically that an important point here is that due to a large value of the lattice-induced dispersion in the PC not only the first term in the expansion of the polarization factor should be considered, but the second one as well, that describes the unusual polarization dependence of the DIPS effect. The results of the theoretical description stay in a good agreement with obtained experimental data. It has been shown theoretically that in a case of nonlinear light-matter interaction for example in low-index layers one of the pulses, the Borrmann pulse, propagates like soliton keeping its shape and constant velocity whereas second pulse, the anti-Borrmann pulse, demonstrate a linear dynamics in dispersive medium.

Research paper thumbnail of Influence of thermal expansion on the feasibility of gamma-ray laser action

Soviet Journal of Quantum Electronics, 1980

It is shown that a stable temperature of the active medium of a gamma-ray laser is essential for ... more It is shown that a stable temperature of the active medium of a gamma-ray laser is essential for its operation. An analysis is made of the influence of thermal expansion of a laser rod cooled with liquid helium on the feasibility of lasing in the presence of heat evolution because of the absorption of electrons and x-ray conversion photons, as well as of cascade gamma photons.

Research paper thumbnail of Polarization and nonlinear effects in diffraction-induced laser pulse splitting in one-dimensional photonic crystals

In this paper, the polarization effects in diffraction-induced pulse spliiting (DIPS) phenomenon ... more In this paper, the polarization effects in diffraction-induced pulse spliiting (DIPS) phenomenon in porous-quartz based 1D photonic crystal (PC) are studied both experimentally and theoretically. The PC was formed with the thickness of each layer of 390 nm and with the period of 780 nm. We made the PC composed of 375 layers, so that the total PC thickness a = 300 μm was large enough for the performance of the experiments in the Laue geometry. The 110 fs light pulses at the wavelength of 800 nm generated by a Ti-sapphire laser were used. The paper demonstrates that the difference in the group velocity of the Borrmann and anti-Borrmann modes is substantially different for the p- and s-polarized pulsed radiation due to a large lattice-induced dispersion in a PC. This leads to a significant change in the value of the splitting time t12 for p- and s-polarized laser pulses propagating within a PC and, in general, in the number of the outgoing pulses as well. After passing a PC the number ...

Research paper thumbnail of Dynamical Bragg diffraction of optical pulses in photonic crystals in the Laue geometry: Diffraction-induced splitting, selective compression, and focusing of pulses

Journal of Experimental and Theoretical Physics, 2012

A theory for the dynamical Bragg diffraction of a spatially confined laser pulse in a linear phot... more A theory for the dynamical Bragg diffraction of a spatially confined laser pulse in a linear photonic crystal with a significant modulation of the refractive index in the Laue geometry has been developed. The diffraction induced splitting of a spatially confined pulse into the Borrmann and anti Borrmann pulses local ized in different regions of the photonic crystal and characterized by different dispersion laws is predicted. The selective compression or focusing of one of these pulses with the simultaneous broadening or defocusing of the other pulse is shown to be possible.

Research paper thumbnail of Dynamical Bragg diffraction of optical pulses in photonic crystals in the Laue geometry: Diffraction-induced splitting, selective compression, and focusing of pulses

A theory for the dynamical Bragg diffraction of a spatially confined laser pulse in a linear phot... more A theory for the dynamical Bragg diffraction of a spatially confined laser pulse in a linear photonic crystal with a significant modulation of the refractive index in the Laue geometry has been developed. The diffraction induced splitting of a spatially confined pulse into the Borrmann and anti Borrmann pulses local ized in different regions of the photonic crystal and characterized by different dispersion laws is predicted. The selective compression or focusing of one of these pulses with the simultaneous broadening or defocusing of the other pulse is shown to be possible.

Research paper thumbnail of Influence of thermal expansion on the feasibility of gammaray laser action

It is shown that a stable temperature of the active medium of a gamma-ray laser is essential for ... more It is shown that a stable temperature of the active medium of a gamma-ray laser is essential for its operation. An analysis is made of the influence of thermal expansion of a laser rod cooled with liquid helium on the feasibility of lasing in the presence of heat evolution because of the absorption of electrons and x-ray conversion photons, as well as of cascade gamma photons.

Research paper thumbnail of Generation of difference terahertz-frequency signals in a system of compound one-dimensional photonic crystals

The possibility of amplification of difference terahertz-frequency signals generated in one-dimen... more The possibility of amplification of difference terahertz-frequency signals generated in one-dimensional nonlinear crystals is studied theoretically. It is shown that the intensity of nonlinear terahertz signals can be considerably increased both due to the coherent summation of waves generated in several photonic crystals and the choice of a special configuration of photonic crystals representing a two-periodic structure.

Research paper thumbnail of Calculating the extended defect contrast for the X-ray-beam-induced current method

Technical Physics Letters, 2012

The contrast of extended defects representing dislocations and grain boundaries has been calcu la... more The contrast of extended defects representing dislocations and grain boundaries has been calcu lated for the X ray beam induced current (XBIC) method. It is established that the maximum contrast increases with the diffusion length of excess charge and decreases with increasing X ray beam width. The sim ulated XBIC profile contrasts are compared to experimentally measured patterns.

Research paper thumbnail of Reconstruction of the surface layer density profile by the X-ray reflectometry method

Crystallography Reports, 2002

ABSTRACT—The method for reconstructing the profile of the material density distribution arbitrari... more ABSTRACT—The method for reconstructing the profile of the material density distribution arbitrarily varying over the depth of the subsurface layer of the specimen from X-ray reflectometry data is suggested. For the first time, the recurrent relationships for the derivatives of the specular reflection coefficient with respect to the parameters of the subsurface layer are obtained, which reduce the volume of the necessary computations by one to two orders of magnitude. The class of functions for which such density-profile reconstruction can be made within a 5% error is characterized. The method is tested on thin tungsten and carbon films on silicon substrates and thin films of porous silicon films with p+-type conductivity. © 2002 MAIK “Nauka/Interperiodica”.

Research paper thumbnail of Diffraction reflection of x-ray radiation with a two-dimensionally bounded wavefront from perfect crystals

Journal of Surface Investigation. X-ray, Synchrotron and Neutron Techniques, 2007

The problem of dynamical diffraction of x-ray radiation with a two-dimensionally bounded wavefron... more The problem of dynamical diffraction of x-ray radiation with a two-dimensionally bounded wavefront is solved in the Bragg and Laue geometries in a crystal with an arbitrary thickness and an arbitrary reflection asymmetry parameter. An analysis of the wavefront deformation during the diffraction and subsequent propagation is carried out. It is shown that the most favorable conditions for the reflected beam to retain its shape are accomplished in a crystal whose thickness is less than the extinction depth.

Research paper thumbnail of Diffraction-induced laser pulse splitting in a linear photonic crystal

Physical Review A, 2009

Temporal Bragg-diffraction-induced laser-pulse splitting into two pulses propagating with differe... more Temporal Bragg-diffraction-induced laser-pulse splitting into two pulses propagating with different group velocities is observed in multilayered linear photonic crystals (PCs). This phenomenon originates from spatially inhomogeneous light localization within the PCs at the Laue scheme of the dynamical Bragg diffraction. In a homogeneous medium at the PC output each pulse is spatially separated into two pulses, propagating in the transmission and diffraction directions, respectively. The experiments are carried out for a one-dimensional porous silicon-based PC consisting of 375 spatial periods of 800 nm thickness using a femtosecond Ti:sapphire laser as a probe. A linear dependence of the time splitting of each pair of transmitted and diffractively reflected pulses on the crystal thickness is demonstrated and is supported by theoretical estimations.

Research paper thumbnail of <title>Temporal and coherence properties of hard x-ray FEL radiation following Bragg diffraction by crystals</title>

Advances in Computational Methods for X-Ray Optics II, 2011

ABSTRACT

Research paper thumbnail of Diffraction-induced spatially confined laser pulse splitting in photonic crystals

Bulletin of the Russian Academy of Sciences: Physics, 2010

It is shown theoretically that the effect of diffraction-induced optical pulse splitting in a lin... more It is shown theoretically that the effect of diffraction-induced optical pulse splitting in a linear photonic crystal under the conditions of the Laue transmission geometric scheme of Bragg diffraction can be realized for a spatially confined laser pulse in a hundred-period multilayer structure.

Research paper thumbnail of Dielectric permittivity in the x-ray region

Soviet Physics Uspekhi, 1978

Research paper thumbnail of Inelastic scattering of x-ray and synchrotron radiation in crystals, coherent effects in inelastic scattering

Soviet Physics Uspekhi, 1977

Research paper thumbnail of X-ray lasers

Soviet Physics Uspekhi, 1975

Research paper thumbnail of Observation of the temporal Bragg-diffraction-induced laser-pulse splitting in a linear photonic crystal

Research paper thumbnail of Amplification of the generation of the sum-frequency signal in multilayer periodic structures at the edges of the Bragg band gap

Journal of Experimental and Theoretical Physics Letters, 1999

Research paper thumbnail of Enhancement of sum frequency generation near the photonic band gap edge under the quasiphase matching conditions

Physical Review E, 2001

We analyze theoretically and study experimentally the mechanisms of enhancement of the sum freque... more We analyze theoretically and study experimentally the mechanisms of enhancement of the sum frequency and second harmonic generation in a finite one-dimensional photonic band gap structure with second order nonlinearity under Bragg diffraction conditions. It is shown that, near the photonic band gap edge, the efficiency of conversion in sum frequency and second harmonic generation processes can be significantly enhanced if two conditions are fulfilled simultaneously: grating assisted phase matching, or quasiphase matching, and an increase of the electromagnetic field density at the fundamental frequencies near the photonic band edges. The role of each mechanism is discussed.

Research paper thumbnail of Observation of optical second-harmonic generation in porous-silicon-based photonic crystals in the Laue diffraction scheme

Research paper thumbnail of Polarization and nonlinear effects in diffraction-induced laser pulse splitting in one-dimensional photonic crystals

2013 Conference on Lasers & Electro-Optics Europe & International Quantum Electronics Conference CLEO EUROPE/IQEC, 2013

ABSTRACT In this paper, the polarization effects in diffraction-induced pulse spliiting (DIPS) ph... more ABSTRACT In this paper, the polarization effects in diffraction-induced pulse spliiting (DIPS) phenomenon in porous-quartz based 1D photonic crystal (PC) are studied both experimentally and theoretically. The PC was formed with the thickness of each layer of 390 nm and with the period of 780 nm. We made the PC composed of 375 layers, so that the total PC thickness a = 300 μm was large enough for the performance of the experiments in the Laue geometry. The 110 fs light pulses at the wavelength of 800 nm generated by a Ti-sapphire laser were used. The paper demonstrates that the difference in the group velocity of the Borrmann and anti-Borrmann modes is substantially different for the p- and s-polarized pulsed radiation due to a large lattice-induced dispersion in a PC. This leads to a significant change in the value of the splitting time t12 for p- and s-polarized laser pulses propagating within a PC and, in general, in the number of the outgoing pulses as well. After passing a PC the number of outgoing pulses can be varied from two up to four in both transmission (T) and diffractive reflection (R) directions, depending on the polarization of the incident radiation and the parameters of a PC. It is shown theoretically that an important point here is that due to a large value of the lattice-induced dispersion in the PC not only the first term in the expansion of the polarization factor should be considered, but the second one as well, that describes the unusual polarization dependence of the DIPS effect. The results of the theoretical description stay in a good agreement with obtained experimental data. It has been shown theoretically that in a case of nonlinear light-matter interaction for example in low-index layers one of the pulses, the Borrmann pulse, propagates like soliton keeping its shape and constant velocity whereas second pulse, the anti-Borrmann pulse, demonstrate a linear dynamics in dispersive medium.

Research paper thumbnail of Influence of thermal expansion on the feasibility of gamma-ray laser action

Soviet Journal of Quantum Electronics, 1980

It is shown that a stable temperature of the active medium of a gamma-ray laser is essential for ... more It is shown that a stable temperature of the active medium of a gamma-ray laser is essential for its operation. An analysis is made of the influence of thermal expansion of a laser rod cooled with liquid helium on the feasibility of lasing in the presence of heat evolution because of the absorption of electrons and x-ray conversion photons, as well as of cascade gamma photons.

Research paper thumbnail of Polarization and nonlinear effects in diffraction-induced laser pulse splitting in one-dimensional photonic crystals

In this paper, the polarization effects in diffraction-induced pulse spliiting (DIPS) phenomenon ... more In this paper, the polarization effects in diffraction-induced pulse spliiting (DIPS) phenomenon in porous-quartz based 1D photonic crystal (PC) are studied both experimentally and theoretically. The PC was formed with the thickness of each layer of 390 nm and with the period of 780 nm. We made the PC composed of 375 layers, so that the total PC thickness a = 300 μm was large enough for the performance of the experiments in the Laue geometry. The 110 fs light pulses at the wavelength of 800 nm generated by a Ti-sapphire laser were used. The paper demonstrates that the difference in the group velocity of the Borrmann and anti-Borrmann modes is substantially different for the p- and s-polarized pulsed radiation due to a large lattice-induced dispersion in a PC. This leads to a significant change in the value of the splitting time t12 for p- and s-polarized laser pulses propagating within a PC and, in general, in the number of the outgoing pulses as well. After passing a PC the number ...

Research paper thumbnail of Dynamical Bragg diffraction of optical pulses in photonic crystals in the Laue geometry: Diffraction-induced splitting, selective compression, and focusing of pulses

Journal of Experimental and Theoretical Physics, 2012

A theory for the dynamical Bragg diffraction of a spatially confined laser pulse in a linear phot... more A theory for the dynamical Bragg diffraction of a spatially confined laser pulse in a linear photonic crystal with a significant modulation of the refractive index in the Laue geometry has been developed. The diffraction induced splitting of a spatially confined pulse into the Borrmann and anti Borrmann pulses local ized in different regions of the photonic crystal and characterized by different dispersion laws is predicted. The selective compression or focusing of one of these pulses with the simultaneous broadening or defocusing of the other pulse is shown to be possible.

Research paper thumbnail of Dynamical Bragg diffraction of optical pulses in photonic crystals in the Laue geometry: Diffraction-induced splitting, selective compression, and focusing of pulses

A theory for the dynamical Bragg diffraction of a spatially confined laser pulse in a linear phot... more A theory for the dynamical Bragg diffraction of a spatially confined laser pulse in a linear photonic crystal with a significant modulation of the refractive index in the Laue geometry has been developed. The diffraction induced splitting of a spatially confined pulse into the Borrmann and anti Borrmann pulses local ized in different regions of the photonic crystal and characterized by different dispersion laws is predicted. The selective compression or focusing of one of these pulses with the simultaneous broadening or defocusing of the other pulse is shown to be possible.

Research paper thumbnail of Influence of thermal expansion on the feasibility of gammaray laser action

It is shown that a stable temperature of the active medium of a gamma-ray laser is essential for ... more It is shown that a stable temperature of the active medium of a gamma-ray laser is essential for its operation. An analysis is made of the influence of thermal expansion of a laser rod cooled with liquid helium on the feasibility of lasing in the presence of heat evolution because of the absorption of electrons and x-ray conversion photons, as well as of cascade gamma photons.

Research paper thumbnail of Generation of difference terahertz-frequency signals in a system of compound one-dimensional photonic crystals

The possibility of amplification of difference terahertz-frequency signals generated in one-dimen... more The possibility of amplification of difference terahertz-frequency signals generated in one-dimensional nonlinear crystals is studied theoretically. It is shown that the intensity of nonlinear terahertz signals can be considerably increased both due to the coherent summation of waves generated in several photonic crystals and the choice of a special configuration of photonic crystals representing a two-periodic structure.

Research paper thumbnail of Calculating the extended defect contrast for the X-ray-beam-induced current method

Technical Physics Letters, 2012

The contrast of extended defects representing dislocations and grain boundaries has been calcu la... more The contrast of extended defects representing dislocations and grain boundaries has been calcu lated for the X ray beam induced current (XBIC) method. It is established that the maximum contrast increases with the diffusion length of excess charge and decreases with increasing X ray beam width. The sim ulated XBIC profile contrasts are compared to experimentally measured patterns.

Research paper thumbnail of Reconstruction of the surface layer density profile by the X-ray reflectometry method

Crystallography Reports, 2002

ABSTRACT—The method for reconstructing the profile of the material density distribution arbitrari... more ABSTRACT—The method for reconstructing the profile of the material density distribution arbitrarily varying over the depth of the subsurface layer of the specimen from X-ray reflectometry data is suggested. For the first time, the recurrent relationships for the derivatives of the specular reflection coefficient with respect to the parameters of the subsurface layer are obtained, which reduce the volume of the necessary computations by one to two orders of magnitude. The class of functions for which such density-profile reconstruction can be made within a 5% error is characterized. The method is tested on thin tungsten and carbon films on silicon substrates and thin films of porous silicon films with p+-type conductivity. © 2002 MAIK “Nauka/Interperiodica”.

Research paper thumbnail of Diffraction reflection of x-ray radiation with a two-dimensionally bounded wavefront from perfect crystals

Journal of Surface Investigation. X-ray, Synchrotron and Neutron Techniques, 2007

The problem of dynamical diffraction of x-ray radiation with a two-dimensionally bounded wavefron... more The problem of dynamical diffraction of x-ray radiation with a two-dimensionally bounded wavefront is solved in the Bragg and Laue geometries in a crystal with an arbitrary thickness and an arbitrary reflection asymmetry parameter. An analysis of the wavefront deformation during the diffraction and subsequent propagation is carried out. It is shown that the most favorable conditions for the reflected beam to retain its shape are accomplished in a crystal whose thickness is less than the extinction depth.