Fast measurement of the laser beam quality factor based on phase retrieval with a liquid lens

摘要

In this paper, a new method for measuring the beam quality (M-2) of lasers based on phase retrieval with a liquid lens is proposed. With intensity profiles obtained under different focal lengths in a certain position, a variable-focus iterative retrieval algorithm is established for the reconstruction of the complex amplitude. Then M-2 can be calculated with the angular spectrum theory. Feasibility of the proposed method is demonstrated with single- and multimode lasers through both simulations and experiments. Compared with the traditional liquid lens method, the M-2 of lasers can be measured faster with the proposed method. (C) 2019 Optical Society of America