High-average-power single-longitudinal-mode pulse laser based on a pulse saturation seed-injection locking OPO

A high-average-power and narrow-linewidth nanosecond (ns) pulse 824 nm laser is a crucial source for the generation of deep-ultraviolet (DUV) 248 nm laser by means of the sum-frequency process with the 354.5 nm laser. To this purpose, in this Letter, we present a seed-injection-locked high-average-power ns pulse single-longitudinal-mode (SLM) 824 nm laser. By developing a novel, to the best of our knowledge, pulse-saturated seed-injection locking method, disturbance of the pulse laser on the locking of the injected seed laser is successfully eliminated. As a result, the output power of 824 nm laser is up to 21.2 W at the incident pump power of 48.1 W, and the pulse width is 15 ns. Especially, the signal-to-noise ratio of the detected modulated sideband signal exceeds 28 dB, which ensures that the achieved linewidth of the 824 nm laser is as narrow as 38.8 MHz. These results demonstrate the potential of the proposed pulse saturation seed-injection locking OPO cavity for high-power and narrow-linewidth laser applications.