Ld Side-pumped Solid-state 266nm Quasi-continuous Ultraviolet Laser Research

LD-pumped all-solid-state lasers become an important branch of laser thechnology field for its many advantages. At present, LD-pumped all-solid-state laser technology have been developed well at several bands and some products were already sold on the market. However, this kind of technology is very rare in short-wavelength UV laser, and most devices are still in the laboratory stage only. In this paper, LD-pumped all-solid-state 266nm UV laser technology was mainly studied. Details are as follows:First, the development process of all-solid-state laser is reviewed, and methods to make all-solid-state ultraviolet laser and some latest research developments and applications, both at home and abroad, is briefly introduced.Second, non-depletion approximation formula frequency conversion efficiency is gained after the deduction of three quasi-monochromati plane wave coupled equations from Maxwell's equations and the result is analyzed; the negative uniaxial crystal theory is also discussed and a theoretical basis to choose a frequency-doubling crystal is proposed, which lay a proper foundation for future crystal choosing.Thirdly, the best intracavity frequency doubling crystal length, and the inter-relationship between pump power and cavity loss is obtained by analyzing intracavity frequency doubling laser's Nd:YAG rate equations gained from the derivation of Q-switch principle conbined with four-level rate equations. And the basic requirements of the laser of acousto-optic Q-technology and Q-implementation is discused as well.Forthly, on the basis of studying many relevant research papers, several different pumping ways and the characteristics of some common laser crystals and a variety of nonlinear frequency-doubling crystal is compared and analyzed respectively; and by using LD side-pumped Nd: YAG crystal with KTP as second harmonic generation crystal of type II phase matching and BBO / CLBO crystal as the fourth harmonic generation crystals of type I phase matching, a high stable UV laser output was realized.Finally, a KTP / BBO / Nd: YAG 266nm UV all-solid-state laser and a KTP / CLBO / Nd: YAG 266nm UV all-solid-state laser were designed. They were side-pumped by LD. And 266nm wavelegth with 76mW and 130mW average output power was gained respectively at the maximum pumping current of 26A , repetition rate of 10KHz. And the explaination of the causes of the elliptical spot and light - light conversion efficiency increased with the increasing drive current have been discussed as well.