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Research On LD Bar Corner-pumped Tem00 CW Composite Nd:YAG Laser And Symmetry Of The Output

Posted on:2011-01-22Degree:DoctorType:Dissertation
Country:ChinaCandidate:S GaoFull Text:PDF
GTID:1118330338990255Subject:Optical Engineering
Abstract/Summary:PDF Full Text Request
This thesis focuses on the LD bar corner-pumped TEM00 CW composite Nd:YAG laser and symmetry of the output.After the fit gain medium and pump source were been chosen, ray-tracing algorithm was used to simulate the pump absorption efficiency and pump absorption distribution of LD corner-pumped laser with different parameters of Nd:YAG composite slab crystal. The optimized slab was designed and manufactured according to the results of the ray-tracing simulating. Resonator experiment was performed to suppress the oscillation of higher-order modes and realize TEM00 operation. Experiment results showed that the output power was 11.94W with the optical-optical efficiency of above 26%, and the M2 factors of beam quality at width and thickness directions were 1.18 and 1.34, respectively. It was the first time that corner-pumped solid-state lasers operated in fundmental mode.For studying the thermal effects which induced the asymmetry of the output of corner-pumped lasers, an appropriate thermodynamics mode was established and finite difference method was used to calculate the temperature distribution of composite slab and the thermal focal length as fuction of pump power. The experimental results agreed well with the calculated results under non-lasing conditions. According to the thermal analysis, heat sink with the adiabatic groove was used to improve the asymmetry of the thermal focal length of composite slab. The numerical analysis indicated that the thermal focal length of two directions could be equal when the width of groove was 0.325 mm and the depth of it was 2 mm. The experiment results showed that the difference of the thermal focal length of two directions decreased from 3.86 times to 2.19 times when the Heat sink with the adiabatic groove was employed. Improving process precision of groove and the calculation taking into account end effect were put forward to ulteriorly improve the asymmetrical thermal focal length.At last, the influence of LD temperature fluctuation on the performance of corner-pumped TEM00 laser was investigated by numerical ray tracing method and laser experiment. At a drive current of 40A, when the LD temperature varies from 15℃to 25℃, the fluctuation of output power is less than 5% and the beam quality remains almost invariable. Furthermore, it could be anticipated that the TEM00 output should still remain stabe, with the LD temperature variation in the range between 10 degree and 30 degree or even in a wider range according to the simulation. Both the theoretical analysis and experimental results show that the corner-pumped TEM00 laser has a good tolerance to temperature fluctuation.
Keywords/Search Tags:corner-pumped, Nd:YAG, composite slab, fundmental mode, symmetry of output
PDF Full Text Request
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