Green light has been popularized in recent years, and the technology has advanced by leaps and bounds, making great progress in China. Although it is very popular abroad, it is still very narrow in the domestic market. In fact, many friends are unfamiliar with this product, don't know what the green laser is used for, and are puzzled about the working principle of this product. It doesn't matter! The staff of Fiber Green Boutique will explain some knowledge in this respect one after another when they are free. This paper mainly explains its generation principle. All semiconductor lasers are focused by laser tubes. The difference between green light and red light is that green light does not directly emit green light, but is converted by crystal. The light beam is then expanded and collimated to produce green light with good focus. 1. Crystal (Nd: YVO4+KTP) Nd: YVO4 crystal is one of the most effective laser crystals used to make all-solid-state laser pumped by laser diode (LD). Its excellent properties include stable chemical and physical processing properties, lower laser threshold, larger stimulated emission cross section, higher slope efficiency and broadband pump light absorption efficiency. Recently, this crystal has been industrialized and widely used in the market by combining with KTP crystal to generate high-power and high-stability infrared and green lasers. KTP crystal: KTP crystal is one of the most comprehensive crystals among many nonlinear crystals at present. It has large nonlinear coefficient, high light damage threshold, high frequency doubling conversion efficiency (> 70%), stable chemical characteristics and relatively low price, which makes it the best crystal material in this kind of crystal application field, especially in the application of 1064nm laser frequency doubling device. LD(808nm)+Nd:YVO4 to get 1064nm+KTP to get 532nm green laser. The green laser module consists of a laser crystal and a nonlinear crystal. In the laser resonator, LD pump light with 808nm wavelength generates 1064nm laser through the gain of laser crystal, and then generates 532nm green laser through the frequency doubling of nonlinear crystal. The green module is similar to the integrated circuit in electronic components, with the characteristics of modularization and integration, which can be mass-produced and reduce the cost. Compared with bonding, the green light module adopts the popular optical bonding technology: there is no optical gap on the bonding surface, the green light output power is high, the output mode is good, and the light spot stroboscopic is low, which can realize continuous and stable output; Under the condition of 200 MW diode pumping, the crystal size is 0.8X0.8X2, and its output green power is generally 5-65438+ 100mw. In addition, the conversion efficiency is closely related to the quality of laser diode and crystal. At present, the most advanced technology and materials on the market can reach the conversion efficiency of more than 35%. Green module is very convenient to make laser resonator, so it becomes the core component of laser diode pumped all-solid-state laser (DPSSL).