M²-factor of high-power laser beams through a multi-apertured ABCD optical system*

Abstract

Based on the generalized truncated second-order moments, an approximate analytical formula of the beam propagation factor M 2 of high-power laser beams passing through the optical system with multiple hard-edged apertures is deduced. Numerical examples of the beams passing through an aperture-spatial filter are enclosed, and the influences of amplitude modulations (AMs) and phase fluctuations (PFs) on the beam propagation quality of high-power laser beams passing through the multi-apertured ABCD optical system are considered and discussed. It is shown that PFs are able to degrade the beam propagation quality of laser beams more than AMs when the high-power laser beams passing through the aperture-spatial filter, furthermore, one or two aperture-lens optical systems configured appropriate aperture parameters are both able to upgrade the beam propagation quality of high-power laser beams. The M 2 factor of Gaussian beam passing through the multi-aperture optical system is a special case in this paper.

A 37 mJ, 100 Hz, high energy single frequency oscillator*

“…[31][32][33][34][35][36][37][38][39][40][41][42] Techniques used for single transverse mode selection include inserted aperture or lens, long cavity, end pump laser, and thermally near unstable resonator. [31][32][33][34][35][36][37][38][39][40][41][42][43] For energy enhancement, a master-oscillator power-amplifier is a well-established technique. [44][45][46][47][48][49][50][51][52] Isyanova reported a 55 mJ single-frequency laser by a MOPA system, and the oscillator has the energy of 0.8 mJ with inserted etalon.…”