.579 Nm, An External Cavity Raman Laser Numerical Simulation And Experimental Study

Yellow laser in the range of 550nm-600nm is widely applied in the fild of biomedical, laser display and satellite guide. Range of applications of the traditional yellow laser is limited by their own insurmountable shortcomings. Solid-state yellow Raman laser occupy an important position in the yellow laser field because of compact structure, stable operation, rich wavelength and high conversion efficiency.577nm wavelength is the absorption peak of hemoglobin. The laser whose wavelength near 577nm can be used for cutting, vaporization, cauterization, cruor, and their clinical treatment effect is perfect. The laser surgical operation is precision, which successfully cure naevus flammeus, ophthalmology, and verruca vulgaris. Because of the special medical value of the 577nm laser, we conducted our study on an external-resonator Raman laser system whose Raman medium is KGW crystal, which is pumped by BBO Q-switched/ Flash-LD-side-pumped module /LBO external cavity frequency doubling 532nm laser.1. The characteristic and progress of solid-state Raman laser which include intracavity Raman laser, external-resonator Raman laser, and self-Raman laser is introduced. It indicates that the performance of the solid state yellow Ramman laser can be improved greatly.2.The operation threshold of the external-resonator Raman laser with KGd(WO4)2 crystal is theoretically predicted by numerical method, which provide optimization of the system.3. In order to increase output power and conversion efficiency of the extracavity Raman laser with KGd(WO4)2 crystal, the radiation transfer equations of the laser system were solved numerically with the methord of area summation. Output intensity of the first to the third stokes with the change of time and the relaxation oscillation of the Raman laser were obtained.The optimum reflectivity of the input and output coupler mirrors at the stokes was figured out.4. We demonstrate the kilohertz operation of an external-resonator Raman laser containing a KGd(WO4)2 crystal as the Raman medium. The pump laser system which has a singly resonant cavity, a Flash-LD-side-pumped module, BBO electro-optical Q-switch and LBO frequency doubling crystal produced 532 nm laser. Using the 532nm laser pump the external-resonator Raman laser system, as much as 650mW of Stokes power is obtained, the conversion efficiency from the pump to the Stokes is 25%. Changing the polarization direction of pump laser,579nm and 588nm Stokes laser was obtained. When the LD pump current is 41A and the reiteration is 1000Hz, the average output power of 579nm is 360mW and the conversion efficiency from the green to the yellow is above 14%.