Narrow-Pulse-Width, Straight-Type-Cavity, All-Solid-State Laser at 228.5 nm

Deep-ultraviolet (DUV) lasers operating at a wavelength of 228 nm offer distinct advantages in Raman spectroscopy and analysis, demonstrating significant potential in the field of surgical medicine. This paper details the development of a high-repetition-rate, narrow-pulse-width, short-cavity laser system functioning at 228.5 nm, which is based on Barium Borate (BBO) electro-optic Q-switching. The system utilizes a double-concave resonator structure and a pressure-applied electro-optic Q-switching technique, incorporating Lithium Borate (LBO) and BBO as frequency-doubling crystals. A low-concentration Nd:YVO4 crystal, measuring 4 mm × 4 mm × 5 mm, serves as the gain medium, with a high-reflectivity coating applied to its left end face to function as the total reflection mirror within the resonant cavity. Upon achieving a pump power of 37 W at a repetition rate of 12 kHz, the system produced a maximum average power of 32 mW, with a pulse width varying from 2.48 ns to 2.70 ns and a central wavelength of 228.5 nm, which is effectively applicable for deep-ultraviolet spectral detection.