Steady state photorefractive gratings in multiple quantum wells at high modulation depth

The steady-state analytical expressions for the space-charge field harmonics generated by the high contrast interference pattern in biased photorefractive material with ambipolar transport are presented. As an example semi-insulating multiple quantum wells film operating in the Franz-Keldysh geometry was considered. Parameters of photorefractive grating created by a quadratic electro-optic effect were analysed. Calculations based on the band transport model were limited to the low external field case what corresponds to the linear transport regime. In particular, it was found that the photogenerated carriers density has nearly harmonic distribution. Moreover, the fundamental component can be obtained from the linear equations what enables us to improve the solution for the space-charge field in bulk, nonresonant materials described by the classical Kukhtarev's model.