DETERMINATION OF LASER-BEAM PARAMETERS WITH THE PHASE-SPACE BEAM ANALYZER

The properties of the phase space beam analyser (PSBA), first introduced by Nemes, were investigated theoretically and experimentally. This optical system enables one to measure far-field divergence and beam radius of a laser beam simultaneously. Experiments were performed with a pulsed Nd:YAG laser with stable and unstable resonators and with a HeNe laser in fundamental mode operation. The theoretical description was based on Fresnel integrals, which were solved numerically using a FFT algorithm. The results presented indicate that the PSBA provides a simple means to determine beam quality and to investigate the mode properties of optical resonators, if diffraction effects are properly compensated.