New approach to solution of photorefractive transport equations

Abstract

Abstract:In our work we propose a novel method of analysis of photorefractive transport equations. The method based on a perturbative approach can be used in the case of two wave mixing and four wave mixing geometry, i.e. for the samples illuminated by interference patterns. Presented approach can be employed for a broad range of material and experimental parameters, particularly for arbitrary depth of light modulation pattern. The approximate analytical solution is compared with results of numerical calculations and a good agreement practically in every case was found. PACS

A general approach to the space–charge field solution in photorefractive materials in a TWM geometry

“…The stationary light excitation pattern acts directly on the carriers; therefore, distributions of electrons and holes are quasi-sinusoidal for any value of m. This observation was confirmed by numerical simulations for the standard PDDT model [21]. Furthermore, a linear solution is a very good approximation of the fundamental harmonic [15]. The higher order harmonics (n ν , p ν ) are much smaller than the fundamental one and their influence on n 1 , p 1 is negligible.…”

“…In our paper we develop a more general approach applicable to the TWM configuration to find the space-charge field profile in a photorefractive crystal. This method was earlier proposed in [15] for the simplest band transport model with one type of charge carrier and one photoactive level of defects. However, the method based partially on the perturbation scheme, can be used for various bipolar band transport models and for a broad range of materials as well as experimental parameters, in particular for arbitrary modulation depth of the light pattern.…”