Self-diffraction of frequency-modulated light in the Bi12TiO20 crystal

The self-diffraction of frequency-modulated light in the photorefractive B₁₂TiO₂₀ crystal was studied experimentally. To observe the effect, the crystal was illuminated by two light beams with the relative frequency shift Δf(t). In the experiments, linear frequency modulation was used: Δf(t) = At. As a result of the light self-diffraction on a hologram moving with a constant acceleration, the power of the light beams at the crystal output changed in the form of a chirp pulse. It was found that the pulse appears at the instant of stopping the interference pattern, and its duration is determined by the rate of frequency change A and the hologram recording time τ _sc .