Complex optical limiting devices based on the z-scan technique: modeling using a numerical mode expansion

Abstract

A numerical approach to analyze the z-scan measurement has been developed for non-Gaussian laser beams. The new approach is based on a mode expansion of the electric field of the laser beam into Gaussian-Laguerre or Gaussian-Hermite modes. The individual modes, appropriate for a laser beam entering the sample, are propagated within the non-linear sample under the influence of the irradiance dependent phase-shifts. The resulting electric field at the exit plane is expanded as a new sum of Gaussian-Laguerre or Gaussian-Hermite modes. The output from one sample can be used as input in a second sample, and hereby the method makes it possible to simulate a variety of complex optical limiting devices. Here we focus the attention to nonlinear optical limiting devices based on two samples, i.e., a tandem limiter. Theoretical simulations are compared with experimental data.