A method is presenting for measuring beam propagation ratios (M2) of laser beam utilizing transmissive liquid crystal spatial light modulator (LC-SLM). In this paper, the function of digital zoom lens (DZL) could be obtained by loading a calculated gray-scale of DZL with desired focal length into the LC-SLM and the accurate focal length of DZL could be gotten by a correction method. By comparing with the standard measuring method provided by ISO (International Standard Organization), through using the transmissive LC-SLM, the beam propagation ratios could be calculated by curve fitting based on the beam spot size collected by digital camera versus the focal length of DZL without any movements in the experiments. The experiment and comparison results have shown that it is effective for us to measure the M2 of Gaussian beam using a transmissive LC-SLM whose experimental setups are simple, relatively.

Date Published: 10 March 2015
PDF: 9 pages
Proc. SPIE 9386, Practical Holography XXIX: Materials and Applications, 938602 (10 March 2015); doi: 10.1117/12.2077952

Published in SPIE Proceedings Vol. 9386:
Practical Holography XXIX: Materials and Applications
Hans I. Bjelkhagen; V. Michael Bove Jr., Editor(s)