The design of green laser pointer can meet current needs of customers

High-power semiconductor laser cavity surface treatment. High-power semiconductor lasers with high power conversion efficiency, small size and many other advantages, in recent years, in addition to pumped Nd: YAG solid-state lasers, fiber amplifiers traditions, but also widely used in the field of laser surgery, physiotherapy and other medical and showing good prospects for application in the field of industrial heat treatment, welding, etc. However, low compared with other lasers, semiconductor lasers, optical power density, current commercial devices of a single continuous output power is only 100W or so, limiting its application to the needs of high optical power density. Pageup function is the newly added function ofchina laser pointer.
If the optical power of the semiconductor laser unit is increased by an order of magnitude, to the scope of application of single-output power in kW or more, will greatly broaden the semiconductor laser materials processing, laser heat treatment as well as laser energy weapons. Leading to COMD failure of the process shown in Figure 1.5. Semiconductor materials, oxidation or other impurities in defects in the laser cavity surface to the deep level (interface states), optical absorption near-cavity surface-generated electron - hole pairs in the cavity surface area by the surface states of non-radiative recombination, so that the heating of the cavity surface resulting in the cavity near the band gap decreases, intensified the cavity surface light absorption, while the current is more concentrated in a narrow band gap region near the cavity surface. Form a positive feedback loop, when the temperature is sufficiently high, leading to the cavity surface burned, that is, COMD. Some modules ofchina laser pointerare easy to be manufactured.
Inhibition of the way of the cavity surface failure. Given above to produce the COMD the several factors, to suppress the cavity surface failure, it is necessary to eliminate or reduce the cavity surface failure caused by link, should be concerned to solve the following problem: to reduce the cavity surface of the non-radiative recombination centers. Cavity surface non-radiative recombination centers mainly on the cavity surface is oxidized to a deep level, the solution is in the process of the cavity surface to prevent oxidation of the cavity surface, or take measures to remove surface oxygen before coating; inhibition cavity surface injection current to reduce the injection current of non-radiative recombination caused by heat; inhibiting cavity near the optical absorption, thereby reducing the light generated carriers, inhibit the current of the cavity surface; to improve the cooling capacity of the cavity of the mask layer. The remote control function ofchina laser pointer is the basis.
Reduce the stress between the cavity surface coating layer and device materials. Semiconductor laser cavity surface when cleavage is very easy to react with the air O, pollution, such as cleavage in a vacuum coating, you can avoid the oxidation of the coating process of cleavage, thereby suppressing the non-radiation of the cavity surface compound. First do the chip in a high vacuum cleaved laser bar, then still under vacuum plated laser-cavity surface-protective film, the anaerobic environment. To non-protective film absorbance materials, and does not react with the cavity surface, which can effectively block the diffusion of impurities from the oxide dielectric film is generally used in ZnSe or Si, Ge and other materials. ZnSe 2.75eV wide band gap and 830nm under the refractive index of 2.5, using electron beam evaporation, the stoichiometric ratio of the film are available at about 700 ℃. The design of china laser pointer should be first-class.
Evaporation at low temperature can reduce the vacuum wall and body cavity other parts of the adsorbed gas discharge, and the lattice constant of ZnSe close of GaAs lattice mismatch of only 0.27%. Through the suppression of the cavity surface near the injection current to reduce the charge carriers injected into the cavity surface, is a simple way to reduce the cavity surface non-radiative recombination. Media oxide isolation in the region near the cavity surface is about 20μm conductive insulating layer (Figure 1.6), in order to prevent the injection current expansion, where necessary, etching away the semiconductor surface of the region of highly doped contact layer. The length of the isolation area should be larger than the average carrier diffusion length, but too much may lead to the decline in the performance of laser PI, so the maximum length shall be designed to compromise to consider. The design of green laser pointer can meet current needs of customers.