Ld End-Pumped All-Solid-State236nm Ultra-Violet Laser

LD end-pumped all-solid-state ultra-violet(UV) laser has advantages such as such as high efficiency, high stability, good quality of light beam, compactness, long lifetime and so on. It is already a central of focus in the field of lasers. The all-solid-state UV laser has become a new generation of ultraviolet laser light source and plays an important role in researches on laser devices. It is widely used in the field of precise materials making, optical chisel, optical printing, spectroscopic analysis, microelectronics, medical treatment and scientific research in general.This paper studied on all-solid-state236nm UV laser theoretically and experimentally. Based on the multiplier theory, phase matching principle and harmonic conversion efficiency were analyzed. The parameters such as nonlinear coefficient, allowing angle and walk-off angle of the second harmonic and fourth harmonic crystal were calculated. The influence on conversion efficiency of incident spot radius was simulated. Designed and optimized the parameters of the folded cavity. The relationship between metastable range of cavity and spot radius was also simulated. The external focus system was designed and the relationship between divergence angle and lens focal length. Based on the theory, LD diode-end-pumped all-solid-state236nm UV laser was set up. At the repetition frequency of20kHz, pulse width199ns,7.8mW236nm UV laser was obtained. The incident power of473nm blue laser was1.174W and the fourth harmonic conversion efficiency of0.86%.