EXPERIMENTAL EFFECTS OF LIGHT-INTENSITY MODULATION ON THE RECORDING AND ERASURE OF HOLOGRAPHIC GRATINGS IN BSO CRYSTALS

Experimental data of the influence of light modulation amplitude m on the photorefractive effect in Bi12SiO20 (BSO) are reported. In these experiments charge diffusion was the unique active transport mechanism. The recording and erasure kinetics are studied in detail for the three first harmonics of the refractive gratings. Differences between linear (m much less than 1 ) and nonlinear regimes were clearly observed. A superlinear dependence of the refractive index change on the light modulation (for large m) has been observed, confirming theoretical predictions.