Efficient 0.75-mJ 100-kHz ultraviolet pulsed laser based on a rod-type photonic crystal fiber

We have developed a high-power ultraviolet (UV) nanosecond-pulsed laser based on a rod-type photonic crystal fiber. The UV pulse energy and the pulse repetition rate are 0.75 mJ and 100 kHz, respectively, yielding 75-W UV average power. The temporal pulse shape and the linewidth of a 1030-nm seed laser are optimized for efficient third-harmonic generation, and the high conversion efficiency of 50% is achieved with a good beam quality (M²∼1.2). To our knowledge, this is the highest UV pulse energy from fiber lasers.