Two-beam coupling on the reflection grating in a Bi12TiO20 crystal

The results of experimental investigations of the dynamics of two-beam amplification on a reflection holographic grating and photoinduced absorption of light at λ = 633 nm in the (100) cut of a B₁₂TiO₂₀ crystal are presented. The numerical analysis of coupled-wave equations taking into account the absorption of light and the vector nature of the coupling in a gyrotropic cubic crystal with a given orientation is carried out. The processing of the experimental data using the scalar approach shows that the two-beam gain on a diffusion-type reflection grating in the B₁₂TiO₂₀ crystal may achieve 4.7 cm^-1, while the additional absorption induced by light amounts to 0.65 cm^-1.