Third-order susceptibility measurements by nonlinear image processing

We present a two-wave mixing configuration associated with a coherent optical processor (4-f system) to characterize the third-order susceptibility coefficient. An accurate measurement of the spatial structure of the intensity becomes possible with a CCD camera, which simplifies and improves the accuracy of third-order susceptibility measurements. To verify the validity of the method, measurements of reference materials illuminated by linearly polarized light are carried out. Good agreement with other measurements by various authors is obtained. (C) 1996 Optical Society of America