Power of Laser Pointer are higher than about 200mW

Power of  Laser Pointer are higher than about 200mW.
Optical information processing and optical storage, optical computer optical coupling of the external device has an important purpose. The advent of the semiconductor laser has greatly promoted the development of information photonics technology, it is the fastest growing in the field of optical communications, the most important important light source of the laser optical fiber communication. semiconductor laser coupled with a low-loss optical fiber, a significant impact on the optical fiber communication, and accelerate its development. Therefore we can say that the emergence of semiconductor lasers, on today's optical communication. GaAs / GaAlAs double heterostructure lasers are important light in optical fiber communication and atmospheric communications, now, all long-distance, large capacity optical transmission systems all use distributed feedback semiconductor lasers . Black material or match can be burnt  by Laser Pointer successfully.
830 nm devices are now widely used for color offset and digital edition print .915 rim of the semiconductor laser used as a fiber laser pump source. Similarly, the 940nm laser used to pump ytterbium laser, of course, as the erbium-doped fiber amplifier 980 nm pump source device market also continues to expand rapidly. In addition, 1.7 headland semiconductor lasers for a number of new medical and military fields, including the target illumination and ranging shorter wavelength lasers are also used in material handling, such as welding, plastic welding, paint stripping, and marking the paper first introduces the semiconductor material to produce the laser required to meet the conditions and operating characteristics, followed by the course of development of the semiconductor laser to further elaborate.
The photoelectric effect was found in 1887 by Hz (HRHertz, 1857 a 1894). The study of the photoelectric effect device is a pumped into a high-vacuum glass balls on the inner surface coated with a photosensitive layer (cathode K), the anode A can be made into a straight line or circular ring. When monochromatic radiation through the quartz window to the cathode K, the escape of electrons from the cathode, e-called photoelectron. If both ends in A, K, coupled with the potential difference U, fly photoelectron in the accelerating electric field under the anode, the formation of the photocurrent in the circuit. The strength of the photocurrent is read by the galvanometer. Like this metal by the irradiation of light and emit electronic phenomenon called the photoelectric effect. For this kind of laser pointer , a piece of AAA battery is enough to switch on the laser pointer.