High-peak-power nanosecond pulsed red laser at 657 nm based on the Nd:YLF dual-crystal scheme

We demonstrated a high-peak-power nanosecond pulsed Nd:YLF dual-crystal-based red laser by intracavity frequency-doubling with a type-I critical phase-matched BIBO crystal. With the aid of the elaborately designed L-shaped resonator and the linearly polarized pump, excellent mode matching and high pump absorption efficiency have been substantiated. Under the incident pump power of 82.7 W, laser emission at 657 nm was realized with the maximum output power of 6.3 W at a repetition rate of 4 kHz. And the average beam quality factor was detected to be M² = 1.68. The pulse energy was scaled up to 3.45 mJ at the repetition rate of 1 kHz, corresponding to a pulse duration of 45 ns and a peak power of up to 77 kW. Additionally, the wavelength could be tuned from 656.3 nm to 657.1 nm after inserting an etalon, with the spectral linewidth all less than 0.05 nm.