green laser pointer should avoid being knocked

Laser TV technology uses video extensively, not only can be used to record television signals, can also become a high recording density, the computer system to facilitate the retrieval part. Laser development is to improve the video recording density, reduce the record size, so that records can be erased with the release and re-recorded with the record.
Capable of firing laser devices. 1954 made the first microwave quantum amplifier, to obtain a high degree of coherence of the microwave beam. The normal working hours of the green laser pointer depend on the frequency applied by it. 1958 AL Xiao Luo and CH Townes quantum amplifier theory to promote the use of microwave to optical frequency range, and that the laser-generated methods. TH Maiman, who in 1960 made the first ruby laser. A. 1961, JIA, who made a helium-neon laser. 1962 RN Hall, who created a gallium arsenide semiconductor lasers. Later on more and more types of lasers. Divided by the working medium, the laser can be divided into gas lasers, solid-state lasers, semiconductor lasers and dye lasers 4 categories. Has recently developed a free-electron laser, the working medium is moving in the periodic magnetic field of high-speed electron beam, laser wavelength coverage from the microwave to X-ray broad band. Divided by work, there are continuous, pulsed, Q-and ultra-short pulse and other types. High-power lasers are usually pulsed output. The page-turning green laser pointer is divided into two parts. A variety of different types of laser wavelength emitted by the laser has reached thousands of species, the longest wavelength of the microwave band of 0.7 mm, the shortest wavelength of 210 angstroms far UV, X-ray lasers are also being studied.
In addition to free-electron lasers, the basic working principle of the laser are the same, an essential component of the device include incentives (or pumping), with a metastable energy level of the working medium and the cavity (see the optical resonator) three parts. Excitation energy is working medium after the absorption of external excitation to the excited state, to achieve and maintain and create conditions for population inversion. Incentives have optical excitation, electrical stimulation, chemical and nuclear energy incentives and other incentives.If you don’t use the receiver, you can put it into the green laser pointer body. Metastable level with a working medium is so dominated by stimulated emission, in order to achieve optical amplification. Resonator cavity photon can have the same frequency, phase and direction of travel, so that the laser has a good orientation and coherence.