Measurement of Coherence and Beam Parameter of a Propagating Laser Beam by using Wigner Distribution Function Measurement

Abstract

The spatial coherence and propagation property of a laser beam propagating through several optical components were studied experimentally by using the Wigner distribution function measurement method. It is shown experimentally that the total degree of coherence, the beam quality parameter, and the near and the far field information of the propagating beam can be obtained from the Wigner function measurement at one plane. More complete characterization of the laser beam was achieved by applying Schmidt mode decomposition to the Wigner distribution function, spatial coherence function, and directional coherence function, respectively. Fine details of the coherence property can be understood by the characteristics of the contributing eigenmodes.