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

Abstract

A general approach to the approximate analytical solution of photorefractive transport equations for arbitrary fringe contrast is presented. The method based partially on the perturbative scheme permits us to find the stationary space–charge field distribution inside a photorefractive crystal for a two-wave mixing (TWM) geometry with a DC electric field. The method can be employed for various band transport models. In the present work two distinct electron–hole conduction models are investigated. The solutions are compared with the results of numerical calculations and good agreement is found.

Perturbative approach to space-charge field dynamics in photorefractive semiconductors

“…It should be noted that the linearization of free carrier distributions n(z), used in theoretical works [2,13], may not be correct at high fringe contrast. For m → 1 even a small contribution of higher components in free carrier densities can lead to significant changes in the profile of the space-charge field due to a strongly nonlinear response of PR material [12]. However, in the framework of the perturbative scheme applicable for a moderate value of m, the inaccuracy in determining n(z) is not enhanced if we take into account the distribution of E sc (z).…”

“…In this case the space-charge field distribution departs from the shape of the light intensity pattern. Up to now many different approaches to finding the electric field distribution at a steady state have been proposed, including approximate analytical solutions [4][5][6], numerical algorithms [7][8][9] and methods applying perturbative techniques [10][11][12].…”

“…Compared to the purely numerical techniques, the perturbative method is much simpler and enables us to derive analytical formulae describing characteristic times of grating evolution. The presented method is partially based on the scheme given in [12].…”

Impact of proton implantation parameters on the photoconductivity of photorefractive multiple quantum wells

“…These phenomena turn out to be crucial from both cognitive and practical perspectives, affecting photorefractive gain during wave mixing [3][4][5] and non-linear propagation of light beams in * E-mail: blazej.jablonski@zut.edu.pl semiconductors [6]. Changes in the mobility result from increasing energy of electrons, which is described as the increase of electron temperature that gets much higher than the temperature of lattice .…”