Laser-diode Side-pump Nd:YAG High Power Ultraviolet Laser

All-solid-state ultraviolet laser has certain advantages of small size, stable performance, long life and so on. This kind of laser is widely used in many fields such as the military, industry and scientific research, especially in precision machining applications. The photon energy of ultraviolet laser is high, which can destroy the molecular bonds directly and not produce excess heat, namely ‘cold machining’. This kind of processing method is of high precision and speed, which is widely used in the fields such as electronics, biological engineering, and 355 nm all-solid-state ultraviolet laser is the most commonly used. All-solid-state ultraviolet laser is divided into end pump and side pump. End pump is with high efficiency, good beam quality and most commercially all-solid-state ultraviolet laser adopts this kind of structure. Several domestic companies such as Huari have developed laser-diode(LD) fiber coupling end-pump commercial 355 nm ultraviolet laser. Although the efficiency of side pump is slightly low, but it has compact structure, standardized module, low cost and easy to achieve high power output. This paper makes full use of the power advantage of side pump laser, using standardized pin side pump coupling module, through the cavity simulation optimization of base mold oscillation beam and crystal rod diameter matching to realize laser near base model output. And a simple structure, high power, low cost 355 nm ultraviolet laser is designed by the double frequency and triple frequency in the cavity. It realizes innovation in engineering application of ultraviolet laser, which has a certain promoting role in application development of ultraviolet laser.In this paper, the related theoretical analysis and experimental research of LD side pump all-solid-state Nd:YAG ultraviolet laser is carried on. The matrix theory is used to simulate the resonant cavity oscillation beam model. The combination of crystal diameter with cavity optimization is controlled to control beam quality. The double frequency and triple frequency in the cavity is used to improve the harmonic conversion efficiency of laser system. And temperature control system is analyzed and designed. According to theoretical analysis, laser experiment system is designed by using the standardized LD pump coupling module with Nd:YAG of 2mm diameter of crystal rod. Then experimental of fundamental frequency, double frequency and 355 nm ultraviolet laser is studied. The laser parameters such as input power, Q- switch frequency which influence on the laser output is analyzed. At the input electric power of 280 W, modulation frequency of 40 k Hz, the maximum output power of 355 nm ultraviolet laser is 10.58 W, with the pulse width of 20 ns, M2=1.3. The theoretical and experimental study show that side-pumped double frequency and triple frequency in the cavity can realize high power output of 355 nm ultraviolet laser which is close to fundamental mode. This kind of ultraviolet laser has simple structure, low cost, which is of great significance in the engineering application development of ultraviolet laser.