High Power All Solid State 355 Nm UV Pulsed Laser

Compared with traditional gas and liquid lasers,laser diode(LD)pumped all-solid-state lasers have the advantages of compact structure,small size,high optical conversion efficiency,good beam quality,stable output power,long working life and adaptability to complex environment,and have been widely used in industrial production.In particular,ultraviolet laser at 355 nm is widely used in industrial processing such as laser marking,material cutting and drilling due to its advantages of large single-photon energy,easy focusing,and strong absorption of most material.However,the research of ultraviolet and deep ultraviolet lasers in China started relatively late.At present,only 355 nm ultraviolet pulse lasers with output power of 3 W and 5 W are mainly sold on the market,which cannot meet the needs of more industrial processing.With the change of the international society,the competition in science and technology has become more and more intense.It is urgent for China to achieve breakthroughs in core technologies in key fields and develop a high-power all-solid-state ultraviolet pulsed laser with completely independent intellectual property rights.On this basis,our research group has developed the development of a 10 W class all-solid-state 355 nm ultraviolet pulsed laser.The main research contents include:1.Based on the analysis of the thermal focal length of the gain crystal in the resonator,the relevant parameters of the resonator are calculated theoretically.According to the calculation results,a“Z”type acousto-optic Q-switched 1064 nm resonator pumped by an888 nm semiconductor laser diode is designed.By optimizing the parameters including the length of the cavity resonator and the transmission of the output coupling mirror,a pulsed1064 nm laser with the average output power of 33.5 W is obtained when the pump power is 85.7 W,which is beneficial to obtain a 10 W 355 nm ultraviolet laser.2.After obtaining a stable 1064 nm fundamental-wave light,a LBO crystal with I-type temperature matching and a LBO crystal with II-type angle matching are used as nonlinear conversion medium for frequency doubling and frequency sum processes,respectively.On the basis of achieving accurate mode matching,a 355 nm ultraviolet laser beam with the output power of 10 W is successfully realized.The measured ultraviolet laser beam quality is M_x~2=1.13,M_y~2=1.02,and the conversion efficiency from pump light to ultraviolet light is 12.5%.The 4-hour power stability is±0.38%.