Optical grating recording in anisotropic photorefractive thin film: Dimensional resonance

A differential equation and boundary conditions are derived for the amplitu de of the first harmonic of the space-charge field in the case of a lossy t hin photorefractive film with anisotropic conductivity that is illuminated by a moving interference pattern. It is shown that for certain values of th e anisotropy parameter, detuning, and film thickness, a new resonance pheno menon may occur. This resonance is distinct from and additional to the one that relies on the agreement between the speed of the interference pattern and that of the space charge wave, and has been known for a long time. (C) 2000 American Institute of Physics. [S0021-8979(00)00610-1].