Perturbative analytical solution of two-wave coupling in photorefractive materials at large modulation depth

Abstract

We apply directly a perturbative expansion to the hopping model of Feinberg. The first three harmonics of the space-charge field are presented, considering the contributions from the higher-order terms at large modulation depth. The dependence of the harmonics on spatial frequency, modulation depth and applied field strength are discussed. An analytical solution of the two-wave coupling equations is given in this case. The mixing gain γ is also discussed.