Research Of Yb:YAG Mode-locking Laser And Optical Properties Of Nonlinear Crystal CBBF

In recent years, DPSSL and the optical frequency conversion technology attracted lotsof fields, and thus it becomes the attention point in the laser research. Themode-locking properties of Yb:YAG/SESAM laser are researched by theoreticalcalculation and the attempt to assemble Yb:YAG/SESAM mode-locking laser isintroduced in this paper. The optical properties of a new nonlinear crystalCsBe2BO3F2(CBBF) are also theoretical analyzed. The main contents include:1. In order to understand the relation of the output pulse properties versus parametersof laser devices, the rate equations of the mode-locked laser and the slow saturableabsorber model are used. The parameters of laser devices include small-signal gain,beam radius, saturation coefficient and saturation fluence. The peak power and pulsewidth of output pulse are analyzed. Then, three types of laser cavities and theirstability are analyzed, which are flat-concave cavity, V-shape cavity and Z-shapecavity.2. Yb:YAG/SESAM mode-locking laser are attempt to build. Flat-concave cavity,V-shape and Z-shape cavity can output the continuous laser and locked mode laser.3. The frequency doubling properties of the novel nonlinear crystal CBBF in type-Iand type-II are researched by theoretical calculation, including phase matching angle,effective NLO coefficient, walk-off angle, permitted angle and permitted wavelength.The results show that CBBF crystal has advantages in a small walk-off angle, largepermitted angle and large peak value of permitted wavelength.4. The conversion efficiency of frequency doubling of CBBF is simulated. Thewavelength of the fundamental wave is1064nm, and the frequency field distributionis the plane wave and the Gaussian approximation. In type-I, the SHG conversionefficiency increase monotonously with the growth of crystal length, and approaches amaximum value. The conversion value of plane wave is100%and70%of Gauss. Intype-II, the conversion efficiency of plane wave varies periodically, and the maximumvalue is78%; the conversion efficiency80%of Gaussian approximation and changesoscillatory.