A new technique for measuring nonlinear refractive index

Summary form only given. The reflection Z-scan technique was recently suggested for the study of nonlinear effects in absorbing materials. This technique allows us to measure the modification in the reflection coefficient of a nonlinear material and to evaluate n, and /spl beta/ from this change. It is less sensitive than the transmission Z-scan technique because the beam distortion caused by the surface reflection is much smaller than the one caused by the transmission through the whole volume of the material. To overcome this small sensitivity, we suggest the use of a polarized incident beam close to Brewster angle. In this case the relative change in the reflection coefficient is increased due to the reduction in the linear term of reflection.