Research on LD-pumped dual wavelength Nd:YAG laser with high beam quality for machining

Abstract

Considering laser medium thermal lens effect and thermal focal length changes with pumping power, conventionally, lasers are designed to operate in the middle of thermal stable zones, where the fundamental mode size is insensitive to thermal perturbation, while this method seems impossible when large fundamental mode size is required. Through self-select mode cavity, lasers are designed to work at the border of stable zone instead, where large fundamental mode size in gain media can be reached. With increase of pumping power and self-aperture mode-selective effect, mode size would grow up automatically to a certain value suitable for monomode resonance. With double 180 W pump modules, acoustic Q-switch and LBO external frequency-doubled, over 28 W which M² equals 4.5 quasi-CW output green laser and 52W 1.064 um IR output is obtained simultaneity. With the insertion or not of the harmonic separator by footswitch high beam quality green IR, and green & IR lasers are obtained conveniently.