Z-SCANS WITH NEAR-GAUSSIAN LASER BEAMS

Abstract

Laboratory measurements of optical nonlinearities can be significantly affected by imperfections in the laser beam profiles. Here the effects of beam profile on Z-scan measurements are calculated for a large number of near-Gaussian beams. These effects are modeled for Z-scans of thin media, for both refractive and absorptive nonlinearities. The difference ∆T between the maximum and minimum values of the normalized transmittance generally increases with the beam quality factor M2 (as the beam quality declines). for a given beam power and waist size. The scatter in ∆T values also increases with M2.