Research Of LD Pumped Solid-state Ultraviolet Lasers

LD pumped all solid state laser has been developed greatly since 1980s, As the use in photophobia , interests in Solid-state UV laser has increased due to the advantages of the high efficiency, impact structure ,better beam quality and high output power. Based on the theory of passively Q-switched laser, the effect of excited state absorption of the passively Q-switched crystal Cr4+:YAG on the pulse laser was considered, as the extend of Degnan's optimization of passively Q-switched laser, the relation between the small-signal transmission of the absorber and the reflectivity of the output coupler was obtained, simplify the design. Under the direction of the theory of the Gauss beam frequency conversion, a more compact structure that satisfied the requirement of both third harmonic generation and fourth harmonic generation was got. For the continuous ultraviolet laser, the relation between the optimum transmission of the output coupler and efficiency of frequency doubling of the laser was considered, then we got the optimum crystal length. Design a stable 1064nm pulse laser with TEM00 mode, peak power above 10kW, pulse width 10ns and single pulse energy 100μJ was obtained. Used a focus spherical lens, two crystal placed around the lens focus position,. when the pumping power was 14.5W ,266nm pulse laser with average power 290mW and 355nm pulse laser with average power 340mW were obtained, both were the best result reported in the country. Used the simple two mirrors cavity, two frequency conversion crystal in cavity,when the pumping power was 5.6W, 355nm CW laser with high output power of 15mw was obtained, until now , this is the best result that reported. But the output power decreased when the pumping power increased. But has self resonant,affect the increase of the power of the UV laser.