Single-beam time-resolved <i>Z</i>-scan measurements of slow absorbers

Abstract

A single-beam time-resolved Z-scan method is introduced to characterize the nonlinear refraction of slow (millisecond) response absorbers with cw radiation. Owing to the elimination of parasitic linear effects, the technique is able to measure induced phase distortions as small as λ/104. We demonstrate this method on several materials using low power Ar+ and He-Ne lasers.