Q switching of a diode-pumped Nd:YAG laser with GaAs

TLDR

The study investigated a diode‑pumped Nd:YAG laser passively Q‑switched by a thin single‑crystal GaAs wafer. The Q‑switching was achieved by the GaAs wafer acting as a saturable absorber. At 3 W pump power, the laser produced stable 7‑ns, 20 μJ pulses at 6 kHz, while up to 2.2 W yielded 13.2‑μJ TEM00 pulses and a 3‑ns minimum pulse width, with two‑photon absorption and free‑carrier effects governing pulse formation.

Abstract

We investigated the properties of a diode-pumped Nd:YAG laser that is passively Q switched by a thin, single-crystal GaAs wafer. At 3 W of incident pump power, the laser produced stable 7-ns pulses with 20 μJ of energy at a 6-kHz repetition rate. For pump powers up to 2.2 W, which resulted in 13.2-μJ pulses, the output mode was TEM00. The shortest pulses that we observed were 3 ns in duration. In addition to saturable absorption, we find that two-photon absorption and free-carrier effects determine pulse formation.