Research On Whole Cavity Water-cooled Radial Slab Solid-state Laser

Because of the high output, high stability and other advantages, solid-state lasers have shown a broad application prospect in industrial processing, lidar, optoelectronic countermeasures, space communications and other fields. Pump energy and temperature distribution inside the laser medium are important factors affecting the performance of solid-state lasers. The slab laser medium can effectively increase the pump surface and the cooling surface to improve the temperature uniformity of the medium, thereby improving the output energy and beam quality of the laser.This paper presents a new scheme of whole cavity water-cooled radial slab solid-state laser. Compared with the conventional way of side cooling, the medium in this paper is immersed in pure water and its side as well as end face can be cooled, so the cooling effect of the whole cavity water-cooled is more uniform. The structure of8radial slab medium, which shares the same resonator is compact, and can obtain a combination of multiple beams. The using of the whole cavity water-cooled can achieve more uniform and efficient cooling effect, then obtaining a higher output power and better beam quality.This paper summarizes the recent development of the slab solid-state laser and multi-beam combination. The advantages and structural characteristics of the slab laser medium are introduced and the distinction between coherent and incoherent combination is analyzed. Combination of multi-beam and beam diffraction theory is derived.According to the theoretical study, the scheme of whole cavity water-cooled is proposed. The system of the whole cavity water-cooled radial slab solid-state laser is designed with the software and the entire laser assembly process is simulated. The feasibility of the design is verified through the experiments. The evaluation methods of beam quality are analyzed theoretically. Appropriate evaluation methods are selected according to features of the far-field beam to analyze the beam quality.According to the design, the whole cavity water-cooled radial slab solid-state laser is assembled and the laser output experiments of near-field and far-field are carried out. There are9beams in the near field (3m) and circumscribed circle diameter is about 30.03mm. The energy is5mJ when the pump voltage is650V and reaches469mJ when the pump voltage is1000V. Pulse width at half maximum is about120μs. In the far field (45m), the beam diameter of9beams combination is92.72mm, and far-field divergence angle is about1.46mrad.Experiments show that the design of the whole cavity water-cooled and8slat laser medium can effectively reduce the thermal effect of the laser medium and improve the distribution uniformity of the pump energy, thereby improving the performance of solid-state lasers effectively. The structure of the laser not only has small size, compact structure, but also can obtain a combination of multiple beams, and has high practical and scientific value.