Direct measurement of the dispersion of the electrogyration coefficient of photorefractive Bi12GeO20 crystals

Abstract

We report on the direct measurement of the electrogyration coefficient of Bi 12 GeO 20 sillenite crystals over the visible spectral range. The coefficient is directly measured on a (111)-cut crystal for which the electro-optic and electrogyratory effects are decoupled. The precision of the measurement method over various parameters including absorption and misorientation is examined. The value of the electrogyration coefficient is found to vary from 0.37± 0.03 to 0.05± 0.01 pm/ V for the 460-760-nm spectrum range, which is within the upper boundaries that have been specified in previous experiments. It is also found that the electrogyration coefficient follows the dispersion law of optical activity and refractive index.

Influence of femtosecond pulsed laser irradiation on bismuth germanium oxide single crystal properties

“…Due to its photoconductivity, photochromism, photorefractivity, piezoelectricity, as well as to electro-optic and magneto-optic effects it supports [7,8], Bi 12 GeO 20 is suitable for a broad range of applications and devices such as optical limiting, holography, spatial light modulation, optical phase conjugation, optical memories, fiber optic sensors, Pockels cells [8][9][10][11][12]. The properties of non-doped as well as doped Bi 12 GeO 20 were investigated and reported in a number of studies, for example in [13][14][15][16][17][18][19][20][21]. Characteristics of Bi 12 GeO 20 single crystals after exposure to thermal treatment [16][17][18][19]22], to beams of electrons [23], uranium ions [24], fluorine ions [15], g-ray [19] or light [9,18,22,[25][26][27][28] were investigated.…”