Generation and Transformation of Partially Coherent Laser Beams

Abstract

The recent progresses in the generation and transformation of partially coherent beams are reviewed. The analytical propagation formulae for the cross-spectral density of the partially coherent anisotropic Gaussian-Schell model (GSM) beams through ABCD optical systems are provided. These formulae provide a powerful tool for analyzing and calculating the transformation of partially coherent GSM beams, such as focusing, spectral shift, and fractional Fourier transform etc. A new kind of resonator with spatial-temporal phase modulation is proposed and analyzed. This kind of resonator can produce partially coherent flattop-alike beams under properly chosen parameters. The changes of the coherence of light in optical resonator are investigated. The generation of partially coherent laser beam directly from spatial-temporal phase modulated optical resonator is investigated experimentally. The results show that intra-cavity phase modulation is an effective way to generate partially coherent beams. The two-slit interference experiment confirms that the output beam is partially coherent.