| LD side-pumped all-solid-state laser is widely used in materials processing,optical fiber communications,medicine,military and so on,because of their miniaturization,high efficiency,wide wavelength range,long service life,compact structure,direct modulation and other advantages.However,due to the laser thermal effects,the output beam quality of laser has been severe impacted and limited the development of the laser.For LD side-pumped Nd:YAG rod pulse laser, we established heat conduction equation with time varying of LD side-pumped Nd:YAG laser basing on the heat conduction theory, and analyzed the influence of LD pump parameters as well as laser crystal parameters on laser thermal effects by means of Matlab software. The method for compensating the thermal effects was proposed and verified by our experimental results.The main research content is as follows:(1) Thermal analysis of physical mode was established and analyzed by Matlab software. The impact of pump intensity,laser waist radius,laser crystal absorbance,radius of the crystal,cooling water temperature,thermophysical parameter,LD duty cycle and other factors were studied on laser crystal core of the section temperature distribution.(2)The variation of OPD was analyzed,which caused by the time varying thermal birefringence effects. Jones matrix was used to process theoretical derivation, which demonstrates that the thermal birefringence effects can be compensated by using 1/4 wave plate in the resonator cavity.(3)To address the problems of spray deposition uniformity of pump light and system cooling,a high energy pulse Nd:YAG laser was designed at proper crystal parameters and resonator structure.We built experiment roof,then used 1/4 wave plate to compensate the thermal effects and measure output laser and laser facula quality.Finally the feasibility of this compensation method was proved by experimental results. |
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