A high-beam-quality Nd:YAG rod laser with a VRM and spherical aberration compensation at 400 Hz

Abstract

A high-beam-quality and high-energy long-pulse laser has been developed with VRM(variable reflectivity mirror)coupling and spherical aberration compensation. The thermal lens and the thermal birefringence are compensated for by the 10 mm DL rod side-pumped laser module. The output mirror employs VRM coupling with R=35% in the center, which presents a energy of 1.04 J at a pulse width of 195 μs and a repetition rate of 400 Hz with a beam quality of M2≈8.4. The spherical aberration compensation improves the beam quality M2 factor to 2.15; the power stability (RMS) is 0.4% at 5 min, and the optical-optical efficiency is 19.7%.