Laser systems pumped by sunlight directly and computer simulation optimization

In order to achieve the conversion from the sunlight to the laser, two-level aggregation experimental system was designed and built. By choosing a Fresnel lens as the first level of aggregation system, the diffuse reflectance tapered cavity as the second level of aggregation system and Nd:YAG as the working substance, the experimental maximum power output was 13.3W available, when the sunlight incident power was about 950W/m2. In order to optimize the experimental system and improve the power output, the resonant cavity was simulated by LASCAD software. The temperature distribution and the refractive index distribution during the working of the crystal rod were obtained. The system was optimized by changing the parameters. The variation of the output power along with the cavity length and the output mirror reflectivity, the best cavity length of 142mm and the output mirror reflectivity of 91% were obtained. The results show that the output power of the laser pumped by sunlight directly can be improved effectively by adjusting the cavity length and the output mirror reflectivity and the best value can be achieved.