Improving side-pumping efficiency of solar-pumped lasers

Solar pumped lasers directly convert sunlight into laser radiation. In this paper, we improve the configuration and structure of the hybrid pumping cavity adding a water-cooling system in the copper cavity. Output laser power is up to 23.7 W, using an Nd:YAG crystal rod with a diameter of 8 mm and a length of 115 mm as laser media, and a 7.87% slope efficiency is achieved. A Fresnel lens with a surface of 1.03 m2 is used as the primary solar light concentrator. It is shown through comparison experiments that the design of the new pumping cavity is an effective solution with a 55.92% increase in output power. We analyze the absorption loss and coupling efficiency of side-pumping light in the new cavity, and confirm that the new structure can improve the side-pumping efficiency. At the end of the article another design of composite cavity with ceramic material is put forward.