Study Of LD Side Pumped High Power All-Solid-State 532nm,355nm Lasers

Diode-pumped all-solid-state lasers (DPSSL) have more advantages than traditional lamp-pumped laser, such as high efficiency, compactness, high stability, and long lifetime. All-solid-state green and ultraviolet lasers have become an enthusiastic focus in the field of lasers due to their many advantages. They are widely used in the field of industry, precise materials making, medical treatment, spectroscopic analysis, optical printing and scientific research in general. In this dissertation the theoretical and experimental researches all-solid-state 532nm green and 355nm ultraviolet lasers are presented. The contents can be outlined as follows:1. The development process of all-solid-state lasers is reviewed firstly. And the main characters of diode-laser pumped solid-state laser and all kinds of LD-pumped crystal material characters are introduced. The domestical and abroad research evolution of LD pumped different wavelength all-solid-state lasers has been summarized. Then the advantages and applications of diode-pumped solid-state ultraviolet lasers are introduced and the recent research evolution at home and abroad of such lasers has been summarized.2. According to the Q-switch theory and nonlinear frequency-doubling and sum-frequency theory, we have researched LD pumped all-solid-state lasers in theory and discussed several elements affecting the efficiency of frequency-doubling such as phase-mismatching and walk-off effect etc. By analyzing the characters of every kind of nonlinear crystal, their advantages and shortness are presented.3. The thermal effects of laser crystal and nonlinear crystal in DPSSL have been researched in great detail. The effects on laser operating have also been discussed. The thermal analysis models of laser devices based on actual characteristic are introduced. Through the heat conductive equations and its boundary conditions, the analytical solution or semi-analytical solution of temperature field distribution and thermal deformation field are obtained. The factors which would influence temperature field distribution of laser device are discussed. The research of thermal effect of laser device will supply a theoretical instruction to effectively solve the thermal effect of laser system, based on which we suggested the methods for eliminating and compensating thermal effects.4. Through investigating the geometrical parameter of resonance cavity and mode parameter in DPSSL, and using the ABCD transfer matrix theory, we properly designed a cavity structure much accordant with our research aim and through which we have performed the experimental researches on LD pumped intra-cavity frequency-doubling green laser. With pumping current 23A and the repetition rate 10kHz, we obtained up to 46W average power green output. And of this device the conversion efficiency is as high as 61.3%, the pulse width is 219ns and the peak power is 21kW.5. Based on the principle of phase-matching and the opticalcharacters of KTP> LBO and BBO crystal, two LBO crystals are selected for the experiment ofintra-cavity 1064nm through frequency-doubling and sum- frequency to generate 532nm green laser and 355nm ultraviolet laser by means of E-0 Q-switch and A-0 Q-switch, respectively using the A-0 Q-switch , for the incident pumping power(808nm) 260W and the repetition rate 4kHz, we obtained 1.5W of 355nm ultraviolet laser output with the pulse width 200ns and the sum- frequency conversion efficiency 2.6%. And using the E-0 Q-switch, for the incident pumping power 240W and the repetition rate lOOHz, we obtained 20mW of 355nm ultraviolet laser output with the pulse width 10ns.