The Relevant Issues Study In Designing High Efficient DPSSL

With the advantage of high efficiency, long life, high stability, high quality beam and compact structure, LD-pumped solid-state laser (DPSSL) has become the focus of international research in the field of lasers.The laser cavity optimization design is one of the important way to improve the conversion efficiency at the limitation of pump source output power . The high conversion efficiency of diode-pumped solid-state laser means that the pump energy can be more effectively converted to the output of DPSSL oscillation light, but the pattern matching between pump light and oscillation light is destroyed by the thermal effect of crystal in the practical application.It results that optical conversion efficiency is decreased and the output power and conversion efficiency is limited.The paper mainly studied two relevant issues in the high efficiency laser design process, which are the selection of the laser medium and the thermal effect on the laser optimization design. The laser crystal that is the heart in the state-solid laser to a large extent determines the laser output characteristics.Some pump energy absorbed by laser crystal converted into crystal thermal energy which formed inhomogeheous temperature distribution within the laser crystal.The effect of thermally induced loss on the output performance of laser is mainly researched in this paper.Under the effect of thermal effect, how to optimize the conversion efficiency of LD end-pumped solid-state lasers is analyzed. Considering the effect of pump beam distribution, the laser medium and resonator structure, a simulation algorithm is designed to calculate the thermal effects and laser conversion efficiency. The results showed that: thermally induced loss is relevant to pump radius, pump power, cavity length, oscillation light radius and crystal materials. It is independent of output mirror transmission and repetition rate. In considering the existence of thermally induced loss, there is an optimum pump parameters and resonator parameters which make the conversion efficiency of Nd: YAG largest when Pump power is fixed.The paper further studied the output characteristics of three different state-solid lasers.Under the same conditions,the conversion efficiency of Nd:YAG,Nd:YVO4 and Yb:YAG were compared.