Nanosecond pulsed Raman yellow laser operating at 573 and 582 nm

A high-beam-quality nanosecond pulsed pro-yellow laser is demonstrated based on an acousto-optically Q-switched intracavity frequency-doubled KGW Raman laser driven by the 1053 nm Nd:YLF laser on the σ polarization. Compared to the π-polarization emission of Nd:YLF crystal, the σ-polarization emission induces a weaker thermal lensing effect, thereby enhancing both the beam quality and thermal stability of the pro-yellow laser without requiring additional optical compensation elements. Two distinct first-Stokes lasers at 1146 and 1164 nm are produced benefiting from the bi-axial properties of KGW crystal, and subsequently frequency-doubled to 573 and 582 nm via a critically phase-matched LBO crystal. Both experimental results and theoretical analysis manifest that the decreased gate-open time within the microsecond range can increase the nonlinear conversion efficiency. Under the incident pump power of 36.9 W and the duty cycle of 1%, the maximum average powers reach 2.5 and 3.4 W with the pulse durations of 8.3 and 7.6 ns at the repetition rate of 5 kHz, respectively. Additionally, at the repetition rate of 1 kHz, the pulse energies are elevated to 2.0 and 2.8 mJ with the pulse durations of 6.2 and 5.3 ns, respectively, corresponding to the peak powers of 323 and 533 kW. The M² factor maintains below 1.6 across the entire output power range.