Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Ferroelectrics

Optical Multivibrator with Ferroelectric Sn2P2S6

Alexandr Shumelyuk, Andrij Hryhorashchuk, Serguey G. Odoulov

Published Mar 20, 2007• 4 citations
Publisher

Abstract

Periodic anharmonic modulation of output intensity is studied for semilinear coherent oscillator with photorefractive crystal that possesses two types of movable charge carriers. The pulse amplitude and modulation frequency are shown to depend considerably on grating spacing of photorefractive grating. We calculate these dependences within the model proposed earlier [A. Shumelyuk, A. Hryhoraschuk, S. Odoulov, Phys Rev. A, 72, 023819 (2005)] and show satisfactory agreement with the experimental data.

DOI
10.1080/00150190701196013

Related papers

Coherent optical oscillator with periodic zero- π phase modulation

Aleksandr Shumelyuk, A. Hryhorashchuk, Serguey G. Odoulov

The four-wave-mixing coherent optical oscillator is described, which is emitting light wave with regular alternation of its phase between two discrete values zero and $\ensuremath{\pi}$. Such a periodic self-modulation is a consequence of competition of photorefractive gratings formed by movable charge species of two different signs. The period of modulation depends on overthreshold coupling strength and on decay time of slow photorefractive grating. It falls to few seconds range for ${\mathrm{Sn}}_{2}{\mathrm{P}}_{2}{\mathrm{S}}_{6}$ crystals at ambient temperature but it can go down to microsecond range for photorefractive semiconductors.

Physical Review A•Aug 22, 2005•18 citations

Optical hysteresis in a semilinear photorefractive coherent oscillator

P. Mathey, Grégory Gadret, S. Odoulov +1 more

High contrast optical bistability is found experimentally in the pump-ratio dependences of the output intensity of a semilinear photorefractive coherent oscillator with two counterpropagating pump waves. The data are in qualitative agreement with the results of calculation.

Journal of Optics A Pure and Applied Optics•Feb 2, 2007•2 citations

Multivalued solutions for the output intensity of a semilinear photorefractive oscillator and stability analysis

P. Mathey, M. Grapinet, Hans Rudolf Jauslin

The analysis of pump-ratio dependences of the output intensity for a semilinear photorefractive coherent oscillator reveals two domains of multivalued solutions for sufficiently large coupling strength ensured by the crystal. We show that even in a strictly degenerate case the nonzero output intensity can be reached in a broad range of pump ratios r from 10−6 to infinity, including the interval where both pump intensities coincide or are very close to each other. This does not contradict the existence of the known gap in the oscillation threshold near the equal intensities of two pump waves: in this particular region the oscillation is not self-starting. The output intensities for frequency degenerate oscillation are calculated analytically in the standard plane-wave approximation of backward-wave four-wave mixing and numerical simulations are used to analyze the stability of multivalued solutions.

Journal of the Optical Society of America B•Mar 15, 2007•4 citations

Manipulation of fast light using photorefractive beam fanning

A. A. Grabar, P. Mathey, Grégory Gadret

Light pulse group velocity manipulations due to the specific dispersion of a medium (so-called “slow” and “fast” light phenomena) can be obtained on the basis of several mechanisms. One of these techniques is two-wave mixing in a photorefractive crystal. This work presents a modification of this method, exploiting the strong beam fanning in Sb-doped Sn2P2S6 crystals. Our experimental results demonstrate a “fast light” behavior of Gaussian pulses transmitted through a Sn2P2S6:Sb sample. The phenomenon is due to the beam fanning (i.e., the self-diffraction of the incident beam on self-induced noisy photorefractive gratings) that ensures a significant depletion of the input beam. Due to the relatively fast photorefractive response of the Sn2P2S6:Sb crystals this depletion occurs with times in the range of 10–100 ms, depending on the beam intensity, and the “fast light” feature is observed. The temporal and amplitude characteristics of the output beam are measured in function of the intensity and polarization azimuth of the incident beam. Besides, a negative phase shift of the periodical output beam relative to a sinusoidal intensity-modulated input beam is also obtained experimentally. It is shown that the phase and amplitude relation between the input and output periodic signals are described by a simple analytical expression that takes into account the beam fanning strength (depletion factor) and its dynamics (depletion time constant). It is also demonstrated that the pulse advance (or phase shift of the modulated signal) can be regulated by the light polarization azimuth. The advantages of the proposed method are discussed.

Journal of the Optical Society of America B•Apr 4, 2014•14 citations

Slowdown and speedup of light pulses using the self-compensating photorefractive response

Boris I. Sturman, P. Mathey, Hans Rudolf Jauslin

We study theoretically the effects of pulse slowdown and speedup in ferroelectric Sn2P2S6 possessing a self-compensating photorefractive response. It is shown that both these effects can be implemented in one sample for sufficiently large values of the coupling strength. In contrast to other types of the photorefractive response (local and nonlocal), the output pulses do not suffer from strong spatial amplification and broadening.

Journal of the Optical Society of America B•Feb 1, 2011•13 citations

Peculiarities of coherent optical oscillation in Sn_2P_2S_6 crystals

Riadh Rebhi, P. Mathey, Hans Rudolf Jauslin +1 more

We show analytically and numerically that the unusual photorefractive nonlinear response of Sn2P2S6 crystals leads to a variety of new features of coherent optical oscillation. In addition to the explanation of the known peculiarities, new features are predicted.

Journal of the Optical Society of America B•Mar 22, 2010•1 citation
Periodic anharmonic modulation of output intensity is studied for semilinear coherent oscillator with photorefractive crystal that possesses two types of movable charge carriers. The pulse amplitude and modulation frequency are shown to depend considerably on grating spacing of photorefractive grating. We calculate these dependences within the model proposed earlier [A. Shumelyuk, A. Hryhoraschuk, S. Odoulov, Phys Rev. A, 72, 023819 (2005)] and show satisfactory agreement with the experimental data.
The four-wave-mixing coherent optical oscillator is described, which is emitting light wave with regular alternation of its phase between two discrete values zero and $\ensuremath{\pi}$. Such a periodic self-modulation is a consequence of competition of photorefractive gratings formed by movable charge species of two different signs. The period of modulation depends on overthreshold coupling strength and on decay time of slow photorefractive grating. It falls to few seconds range for Sn2P2S6{\mathrm{Sn}}_{2}{\mathrm{P}}_{2}{\mathrm{S}}_{6}Sn2​P2​S6​ crystals at ambient temperature but it can go down to microsecond range for photorefractive semiconductors.
The analysis of pump-ratio dependences of the output intensity for a semilinear photorefractive coherent oscillator reveals two domains of multivalued solutions for sufficiently large coupling strength ensured by the crystal. We show that even in a strictly degenerate case the nonzero output intensity can be reached in a broad range of pump ratios r from 10−6 to infinity, including the interval where both pump intensities coincide or are very close to each other. This does not contradict the existence of the known gap in the oscillation threshold near the equal intensities of two pump waves: in this particular region the oscillation is not self-starting. The output intensities for frequency degenerate oscillation are calculated analytically in the standard plane-wave approximation of backward-wave four-wave mixing and numerical simulations are used to analyze the stability of multivalued solutions.
Light pulse group velocity manipulations due to the specific dispersion of a medium (so-called “slow” and “fast” light phenomena) can be obtained on the basis of several mechanisms. One of these techniques is two-wave mixing in a photorefractive crystal. This work presents a modification of this method, exploiting the strong beam fanning in Sb-doped Sn2P2S6 crystals. Our experimental results demonstrate a “fast light” behavior of Gaussian pulses transmitted through a Sn2P2S6:Sb sample. The phenomenon is due to the beam fanning (i.e., the self-diffraction of the incident beam on self-induced noisy photorefractive gratings) that ensures a significant depletion of the input beam. Due to the relatively fast photorefractive response of the Sn2P2S6:Sb crystals this depletion occurs with times in the range of 10–100 ms, depending on the beam intensity, and the “fast light” feature is observed. The temporal and amplitude characteristics of the output beam are measured in function of the intensity and polarization azimuth of the incident beam. Besides, a negative phase shift of the periodical output beam relative to a sinusoidal intensity-modulated input beam is also obtained experimentally. It is shown that the phase and amplitude relation between the input and output periodic signals are described by a simple analytical expression that takes into account the beam fanning strength (depletion factor) and its dynamics (depletion time constant). It is also demonstrated that the pulse advance (or phase shift of the modulated signal) can be regulated by the light polarization azimuth. The advantages of the proposed method are discussed.