Narrow-linewidth UV laser source at 257 nm

There is an increasing need for narrow linewidth, high average power ultraviolet (UV) laser sources for high resolution spectroscopy, remote environmental sensing, laser-induced fluorescence, semiconductor inspection, and LIDAR applications [1,2]. A way to design efficient sources in the UV is to frequency convert diode-pumped solid-state lasers that emit in the near infrared (IR) [3]. In this case, obtaining high nonlinear conversion efficiency requires a large peak power in the fundamental wave. At a fixed repetition rate and average power, this results in a tradeoff between attainable linewidth, related to the pulse duration, and the nonlinear conversion efficiency.