Optimal Design Of Concentrating System For Solar Pumping Solid-state Laser

Solar laser is one of the effective ways to solve the depletion of traditional fossil energy and the environmental pollution.It has broad application prospects in many space fields including space solar power stations,wireless energy transmission,solar laser weapons,and space laser communication.Improving the concentration efficiency and spot uniformity of the solar-laser concentration system is one of the key technologies of the solar pumped solid-state laser.The thesis consists of three parts.Firstly,the solar concentration system including Fresnel lens and the dielectric-filled compound parabolic concentrator(CPC)is investigated.The effects of different filling materials of dielectric-filled CPC,maximum receiving half-angle,distance from the Fresnel lens,and upper and lower intercept ratios on the concentration efficiency and spot uniformity are analyzed.The results show that the dielectric-filled CPC can effectively improve the total concentration efficiency.The maximum solar concentration efficiency of dielectric-filled CPC filled with F13 can reach 64.1%,which is 13.7% higher than the maximum concentration efficiency of total reflection CPC.However,the uniformity of the light spot has decreased.Then,a secondary concentration system composed of a rectangular parabolic mirror and a rectangular dielectric-filled CPC was used to pump the slab laser medium.The side size of slab is 2mm×20mm.The results show that the concentration efficiency is 81.3%,and the uniformity of the converging light spot can reach 91.2% after optimization of concentration system.Finally,a concentration system composed of a new multifocal total reflection Fresnel lens,a solid CPC and a homogenizer was demonstrated.Through Trace Pro software simulation,it can be known that the uniformity of the spot after the optimization of the concentration system composed of non-equidistant and total reflection Fresnel lenses can reach 88.8%.At this time,the concentration efficiency of the system is 82.2%.When the concentration system based on a single-focus total reflection Fresnel lens is optimized,the uniformity of spot can reach 85.1% and the concentration efficiency is 87.4%.These results can provide significant references on the design of the concentration system for solar pumped solid-state laser.