High efficiency near TEM 00 mode compact 355 nm ultraviolet laser

Abstract A compact 355 nm ultraviolet (UV) laser with high conversion efficiency and beam quality is demonstrated. The system employed a 0.3 at.% Nd:YVO ₄ crystal pumped by an 878.6 nm diode source. For frequency doubling, two LBO crystals of different lengths (10 mm and 12 mm) were used to analyze the optimal conversion efficiency for frequency tripling. Subsequently, a Brewster-cut LBO crystal was employed for intracavity third harmonic generation. At a pump power of 29.4 W and a repetition rate of 45 kHz, the laser delivered an average output power of 5.8 W with a pulse duration of 11.2 ns, corresponding to a pump-to-UV conversion efficiency of 19.73%. The beam quality factors of the 355 nm laser were M x 2 = 1.040 and M y 2 = 1.047, respectively.