This article describes the characteristics of the green laser.
Green laser: UV lasers and deep ultraviolet lasers have a wide range of applications in industry, medicine, printing, etc. The use of green light as a pump source is currently the most effective and widest method of generating ultraviolet and deep ultraviolet lasers.
Green laser generation method
(1) The up-conversion pump emits green light laser doped with rare earth ions in the solid material, pumped with a semiconductor laser or other light source, and directly uses the energy level transition of the rare earth ions to generate green laser light. This method is based on the up-conversion effect, that is, the wavelength of the laser light is smaller than the wavelength of the pump light. The up-conversion luminescence mechanism of rare earth ions can be generally divided into three processes: excited state absorption, energy transfer and photon avalanche.
(2) The semiconductor laser emits green light directly. The semiconductor laser is a miniaturized laser that uses a PN junction or a PIN junction composed of a direct band gap semiconductor material as the working substance. There are three main excitation methods for semiconductor lasers, namely, electric injection type, optical pump type and high energy electron beam excitation type. By wavelength
And application fields, semiconductor lasers can be roughly divided into two types: long wavelength and short wavelength. On the short-wavelength side, due to difficulties in material preparation and device technology, the research progress of semiconductor green lasers has been relatively slow, and it has not reached a practical level for a long time.
(3) Nonlinear optical crystal frequency doubling method This is the more commonly used method to realize green laser. This method can be divided into direct method and indirect method. The direct method is to directly input the semiconductor laser to the wavelength conversion element and obtain the green laser output after frequency doubling. This method is characterized by simple structure, easy frequency doubling, and high conversion frequency, but the output green laser has a wide linewidth and poor wavelength stability. The indirect method can be divided into two types: a. The solid-state laser activated by rare-earth ions such as Nd3 + and Er3 + is pumped by a semiconductor laser, and then the frequency conversion element is used to achieve frequency doubling. This method is more complicated in structure, but can get good laser spectrum and beam characteristics. In addition, this method can also take advantage of the long life of the solid-state laser to achieve energy accumulation, thereby obtaining high-energy laser output. b. Use self-frequency-doubling crystal materials that can both emit laser light and achieve wavelength conversion at the same time to achieve laser output, such as Qian Ni and MgO co-doped potassium nitrate, aluminum borate and KTP: Cr.
Implementation method of green laser
For green lasers, there are several methods for obtaining green light:
(A) Non-linear effect realizes frequency conversion: the green light output of 532nrn can be obtained by solid-state laser such as Nd: YAG or Nd: Yvo4 output laser with a wavelength of IO64Iun using a non-linear crystal frequency doubling or Yb3 + or N + The 1.0-1.2um band laser output by the ion fiber laser is frequency-doubled by a nonlinear crystal to obtain a green light output. The research and industrialization of solid green lasers abroad are quite mature. For example, in 2005, Japanese T. Kojima and others obtained a green light output of 400w. In the same year, the Institute of Physics of the Chinese Academy of Sciences used a folding cavity to output an average power of 121w. Green light. Foreign countries have developed rapidly in green fiber lasers. In 2000, the UK used ytterbium-doped fiber amplifiers to obtain a 6w green light output after frequency doubling with KTP crystals. In 2009, Japan ’s Momokoaka and others used two frequency-doubled DKDP crystal pairs. A large numerical aperture Nd: glass laser undergoes frequency conversion to obtain a pulsed green light output of 75. Domestically, it is relatively slow. In 2004, Shanghai Optoelectronics Co., Ltd. used a PPLN crystal frequency doubler to output 59mw of green light for the ytterbium-doped fiber laser. In 2007, Tianjin University used PPKTP crystal to double the frequency of a fiber laser with an output of lo64nln to obtain green light with an output power of 0.14mw. The Qin-doped green fiber laser in China is not very mature, so it is very meaningful to study it. Moreover, compared with the solid green lasers that are well-developed at present, fiber lasers have the advantages of high efficiency, good heat dissipation, small size, low closed value, tunable, narrow line width and compact structure. Pseudo) for a semiconductor laser with an output wavelength of near-infrared (frequency doubling or sum frequency I`.40]: plus TI developed in Germany in 2007: TI: Sappre semiconductor laser and another mid-infrared semiconductor laser output via BBO sum frequency Compared with the method (a), the green light with a wavelength of 527nln has the disadvantage that the beam quality of the output laser is poor.
If you want to know more, our website has product specifications for green laser, you can go to HongDa ELECTRONICS to get more information