Polarization properties of self-diffraction in sillenite crystals: reflection volume gratings

Abstract

International audienceWe study two-beam interaction in photorefractive sillenite crystals in reflection geometry and derive analytic expressions for the signal gain and its polarization direction in the presence of a strong pump beam. The crystal is cut normal to one of the crystallographic axes, and no external electric field is applied. Crystal absorption and its natural optical activity are taken into account. The coupling effects are strongly dependent on the polarization directions of the interacting beams. We determine the optimal polarization directions and optimal crystal thickness that give maximum signal gain. Experimental results are in excellent agreement with theoretical calculations

Hologram recording and reading in cubic gyrotropic photorefractive piezocrystals (review)

“…Reflected holograms in optically active cubic crystals were examined in many studies [113,[126][127][128] in terms of only the electro-optical mechanism of the photorefractive effect although they were already investigated taking into account the piezoelectric effect [70,[129][130][131][132][133][134][135][136][137][138]. Especially interesting effects were observed during a study of the output energy characteristics of phased reflected holograms in cubic optically active photorefractive piezocrystals as a function of crystal thickness [130,133,[135][136][137][138].…”

Contribution of the inverse flexoelectric effect to counterpropagating two-wave mixing of light beams in photorefractive crystals

“…In the absence of an external field, a significant photorefractive response can be achieved in electro-optic crystals with counterpropagating mixing of light waves on a volume reflective hologram formed using Densiyuk's layout. [8][9][10][11][12][13][14][15] One possible application of volume holograms in photorefractive crystals is a laser interferometer. [1][2][3][4][5][6][7]11,[14][15][16][17] Laser interferometers convert phase modulation of light into intensity modulation, and this allows the mechanical vibrations of surfaces that reflect or scatter the light beams to be measured with high accuracy.…”

“…The dynamic character of the holograms in photorefractive crystals, which have a finite response time when they are overwritten, makes it possible to carry out adaptive processing of nonsteady-state light-field patterns in laser interferometers, ensuring both effective phase demodulation and the compensation of the low-frequency modulation caused by the slow drift of the external conditions. Counterpropagating wave mixing, used in such crystals to form effective reflective holograms by a diffusion mechanism in the absence of applied external electric fields, [8][9][10][11][12][13][14][15][16][17] is attractive for adaptive laser interferometry.…”

Two-beam coupling on the reflection grating in a Bi12TiO20crystal

“…The two-beam coupling on reêection gratings in the (100) cut of doped Mn:Bi 12 TiO 20 and Cd:Bi 12 TiO 20 crystals was studied in Ref. [6]. The lower optical activity of Bi 12 TiO 20 made it possible to obtain the gain of the signal beam more than double the value for bismuth silicate.…”