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The Ld End-pumped Nd: The Yvo <sub> 4 </ Sub> Laser

Posted on:2009-10-06Degree:MasterType:Thesis
Country:ChinaCandidate:J J WangFull Text:PDF
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Nd:YVO4 crystal is famous for its excellencies of high absorption cross-section,high emission cross-section and polarizing output laser. Due to the 1342nm laser obtained by Nd:YVO4 laser is near the areas of eye safety and low loss and disperse of optical fiber, it has extensive application in laser medical, fiber communication, fiber Sensing positioning and mid infrared optical parametric oscillator. 671nm red laser which is its frequency-doubled laser is corresponding the highest spectrum sensitivity of Color Holography photographic glue layer, so it can be used to be pump source of the other laser such as Cr:LiSAF laser. On the side, with nonlinear crystal such as KTP and LBO, 593 nm Yellow Laser generates simultaneous laser action at wavelength 1064 nm and 1342 nm produced by laser-diode-pumped Nd:YVO4 laser.Comparison of the output power in different cavity length and different curvature radius of input mirror, the highest slope efficiency was about 22% in laser-diode end-pumped Nd:YVO4 laser at 1342nm. It was seen that when the pump power was low, the output power increased linearly nearly; when it exceeded a certain range, the slope efficiency decreased, especially for the longer cavity in which output power descended with pump power increasing. Then TEM00 mode size in crystal and thermal induced diffraction losses was calculated in theory. The results showed that Thermal effect had influence on the output power of laser, TEM00 mode size in crystal without thermal effect to pump beam sizeω/ωp was preferable between 0.8 and 0.9 at high pump powers to gain larger output power and the ratio would be less with the larger pump power. The experimental results agreed with theoretical predict.Output power of laser-diode end-pumped Nd:YVO4 / KTP frequency- doubled Laser was studied at different cavity structure. The red laser was obtained with effective frequency-doubled efficiency 10.8% in the optimal folded angle 25°. The 3-mirror folded resonator was optimized by the research about influence of parameters including the resonator length, curvature radii of mirrors, Nd∶YVO4 and KTP thermal effect on the resonator stability and basic mode size of Nd∶YVO4 crystal. The optimum folded angle was obtained by the Jones matrix method which was first used to analyze the effect of folded angle on the output power. This work made the theory of folded Resonator laser perfect further.The research was about 593nm yellow laser obtained by Nd:YVO4 / KTP intracavity sum-frequency mixing in plane-concave cavity. Phase matching condition of sum-frequency crystals KTP and LBO was compared in theory. Based on the conditions of multiwavelength oscillation criterion, the result was that when the reflectivity of input mirror to 1342nm was 99.7%, the reflectivity of it to 1064nm was 97.3%. In this precondition, when the input power was 9.1W, the ratio of intracavity power of two wavelength laser was 1.26. The theory coincides essentially with the experiment.
Keywords/Search Tags:Laser-diode -pumped Nd:YVO4 laser, 1342nm laser, KTP intracavity frequency doubling, Jones matrix method, Sum-frequency
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