Abstract

In thin photorefractive materials beam coupling can be observed in the Bragg, Raman-Nath and intermediate regimes, dependent on the geometrical properties of the incident optical beams [1]. By varying the grating spacing, achieved by changing the angular separation of the beams which create the grating, it is possible to move from Raman-Nath to Bragg regime. Application of simple Bragg [2,3] or Raman-Nath [4] models to a system in the intermediate regime could potentially lead to the derivation of incorrect coupling coefficients.

© 2009 IEEE