Abstract

The theory describing the oscillations of holographic gratings in photorefractive crystals due to periodical phase modulation of one of the recording beams has been developed for the linear and nonlinear regimes of recording. A sharp resonance for the non-Bragg diffraction orders and for the drift mechanism of recording was predicted for the case when the frequency of phase modulation Ω and grating wave vector k obey the dispersion law Ω ≈ (kτL)^-1, where τ is the Maxwell relaxation time, L is the drift length, and kL ≫ 1 [1]. This resonance is attributed to the resonance excitation of moving holographic gratings which we call photorefractive waves. The photorefractive waves are characterized by the amplitudes, frequencies, wave vectors, dispersion relationships, speeds of propagation, and relaxation rates.

© 1998 IEEE