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Study On The Intracavity-Pumped Quasi-Three Level Blue Laser Based On Sum-Frequency Mixing

Posted on:2012-02-01Degree:MasterType:Thesis
Country:ChinaCandidate:X J YanFull Text:PDF
GTID:2218330362951379Subject:Optics
Abstract/Summary:PDF Full Text Request
Blue laser has a wide prospects of applications. However, the achieved laser radiations in the blue spectral region are limited, and the traditional methods to obtain blue lasers have their own defects. Besides, the technique of obtaining blue radiations by sum-frequency mixing (SFM) is not yet mature, and the corresponding costs are relatively high. Therefore, few such blue lasers can commercially available in the laser market. Considering the technical difficulties in the field of SFM blue laser, we novelly explored a simple and efficient way to achieve blue laser radiation: A LD pumped 914nm quasi-three level Nd:YVO4 laser was used to intracavity pump the Yb:YAG crystal to obtain 1030nm radiation which was sum-frequency mixed with the residual optical field at 914nm in a BiBO crystal to generate 484nm blue laser.Firstly, based on the coupled equations, the gain theory of SFM both in small signal approximation and high conversion efficiency condition was discussed. Moreover, theories of quasi-three level rate-equation and sum-frequency mixing were used to deduce the rate-equation of intracavity-pumped SFM laser, and the corresponding theoretical model was established. The expression of threshold power was further deduced by solving the above rate-equation.Secondly, the optical cavity, laser crystal and nonlinear crystal for SFM were introduced. Considering the characteristics of different cavities, the Z-shaped cavity was chosen as the resonator of this research, and the advantages and stability properties of such kind of cavity were also analyzed. On the other hand, the physical and chemical properties of the Nd:YVO4 and Yb:YAG crystals, and also the absorption and fluorescence spectrum of the two kinds of crystal were presented. In addition, the optical properties of the BiBO crystal were discussed, and the phase-matching angle for 914 and 1030nm wavelengths, namely the cutting angle of BiBO, was calculated by numerical method.At last, the parameters of optimized beam size, radius of curvature of different cavity mirrors and cavity length of the resonator with multi-elements were calculated. Furthermore, the 914nm fundamental laser with two different types (linear and Z-shaped) of cavities and pumped by a 808nm LD was experimentally realized. Besides, the reason why the another fundamental laser (1030nm) failed to resonate was analyzed, and the corresponding solutions were also given.
Keywords/Search Tags:sum-frequency mixing, Intracavity-pumping, quasi-three level, blue laser
PDF Full Text Request
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