Research Of LD Side-pumped Nd:YAG Slab Laser Resonator

Solid-state lasers traditionally are fabricated in the shape of a long thin rod, which exhibits optical distortions such as thermal focusing, thermal stress induced birefringence in the case of high power operation. These thermally induced effects severely degrade the optical quality of the laser beam and eventually limit the laser output power. Both theories and experiment results show that novel slab lasers are of advantage to eliminate those thermal focusing effects, improve the optical quality and increase the output power. This dissertation presents results of edge-pumped slab laser based on a series of theoretical and experimental researches. The contents can be outlined as follows:(1) The advantages of slab lasers are reviewed. The development of LD pumped slab lasers in China and foreign countries are summarized.(2) Advantage and disadvantage of edge-pumed and end-pumed laser have been analyzed , structure of slab module and laser-diode stack used in this subject have been present.(3) Thermal lensing of two dirction has been measured. Thermal lensing formula of y-z dirction has been given by one-dimensional thermal distributing module of Nd:YAG slab. Calculate results and experiment results have been compared.(4) Multi-pass folded resonator has been analyzed by g~* method and beam transfer matrix method. The influence to stabily caused by resonator length,radius of reflection mirror and thermal lensing in x-z direction and y-z dirction have been analyzed.And influence to beam semidiameter and divergence angles caused by these factors have been analyzed based on stabilty resonator.A set of suitable resonator parameter which insured resonator's thermal stabily has been given.The mode volume, divergence angles and M~2 factor have been calculated.(5) Small signal gain coefficient of Nd:YAG slab laser has been calculated. Gain distribution on different place of slab module end has been measured.The calculate result and experiment result have been compared. Single pass wasting has been calculated and measured. (6) Based on these results,when beam transfers 5 times in slab crystal using multi-pass folded resonator, optimal output of Nd:YAG slab laser has been given.