> 6 W 320 nm ultraviolet pulse laser based on intracavity frequency doubling of Pr:YLF crystal

By optimizing a laser crystal and resonator structure, we obtained a series of the best experimental results of Pr³⁺-doped solid-state lasers, including a 10.8 W continuous-wave (CW) laser, a 5.29 W acousto-optical (AO) Q-switched laser, and a 6.03 W AO Q-switched, intracavity frequency-doubled laser. With a 0.1 at.%, 18 mm Pr:YLF crystal as the laser medium, when the absorbed pump power was 23 W, a maximum CW output power of 10.8 W was achieved at 640 nm, with a slope efficiency of 56.6%. The laser output exhibited excellent beam quality (M_x²=1.26, M_y²=1.22) and remarkable power stability (RMS = 0.16%). For AO Q-switched pulse laser operation at 640 nm, a maximum average output power of 5.29 W was achieved at a repetition rate of 40 kHz. When the repetition rate was 10 kHz, a maximum single pulse energy of 342 μJ was realized. With a (<i>θ</i> = 90°, <i>ϕ</i> = 53.6°)-oriented, 10 mm LBO crystal as the nonlinear optical medium, the AO Q-switched, intracavity frequency-doubled ultraviolet (UV) laser properties at 320 nm were researched at different repetition rates. The highest average output power of 6.03 W was obtained at a repetition rate of 40 kHz, the largest single pulse energy of 333 μJ and the highest peak power of 6.05 kW were achieved at a repetition rate of 10 kHz. The laser output also exhibited excellent beam quality (M_x², M_y²<1.3) and power stability (RMS < 1%). The high quality, compact 10 W visible laser at 640 nm, and 6 W UV laser at 320 nm, will be very favorable for many practical applications, like biomedical, micro-nano processing, and generating sources for shorter wavelength deep UV lasers.