UV 20W-class single-mode nanosecond pulse delivery using a vacuum-free/ambient air inhibited-coupling hollow-core fiber

Silica fibers have been successfully used to deliver high-power high-energy laser beam in the near-infrared and visible range but suffer from high absorption and color-center formation in the UV spectrum which disqualify them for such wavelength. Recently, the advances of inhibited-coupling hollow-core photonic crystal fibers have made them an unique tool to transport UV radiation thanks to an ultralow overlap with the silica cladding and record losses down to 10 dB/km. By further optimizing such fiber, we report in this letter a record single-mode delivery of 23.3 W (155 μJ) with 92% transmission from a 343 nm, 10 ns, 150 kHz laser source, corresponding to an improvement of the current state-of-the-art by two orders of magnitude.