What is "stimulated radiation"? It is based on a brand-new theory put forward by the great scientist Einstein in 19 16. This theory means that there are different numbers of particles (electrons) distributed in different energy levels in the atoms that make up matter. When a high-level particle is excited by a photon, it will jump from the high-level to the low-level level. At this time, they will emit light with the same properties as the light that excites them, and in a certain state, weak light can also excite strong light. This is called "optical amplification of stimulated radiation", or laser for short. Laser has four main characteristics: high brightness, high directivity, high monochromaticity and high coherence.
High laser brightness: the brightness of solid-state laser can be as high as1011w/cm2sr. Moreover, after the high-brightness laser beam is focused by the lens, it can produce thousands or even tens of thousands of degrees of high temperature near the focus, making it possible to process almost all materials.
High directivity of laser: The high directivity of laser enables it to effectively transmit a long distance, and at the same time, it can ensure the high power density of focusing, both of which are important conditions for laser processing.
High monochromaticity of laser: Due to the high monochromaticity of laser, the beam can be accurately focused on the focus and high power density can be obtained.
High coherence of laser: Coherence mainly describes the phase relationship of each part of light wave. It is laser that has the above peculiar characteristics, so it has been widely used in industrial processing.
At present, laser has been widely used in laser welding, laser cutting and laser drilling (including oblique holes, irregular holes, gypsum holes, tipping paper holes, steel plate holes, packaging and printing holes, etc.). ), laser quenching, laser heat treatment, laser marking, glass carving, laser fine adjustment, laser lithography, laser film making, laser film processing, laser packaging, laser circuit repair, laser wiring technology, laser cleaning, etc.
After more than 30 years of development, lasers are almost everywhere now. It has been used in all aspects of life and scientific research: laser acupuncture, laser cutting, laser welding, laser quenching, CD, laser rangefinder, laser gyroscope, laser straightener, laser scalpel, laser bomb, laser radar, laser gun, laser cannon and so on. In the near future, lasers will definitely be more widely used.
Laser weapon is a kind of directional energy weapon, which directly destroys or paralyzes the target by using directional laser beam. According to different operational purposes, laser weapons can be divided into tactical laser weapons and strategic laser weapons. The weapon system is mainly composed of laser, tracking, aiming and launching devices. At present, the commonly used lasers are chemical lasers, solid-state lasers and CO2 lasers. Laser weapons have the advantages of fast attack speed, flexible steering, accurate attack and no electromagnetic interference, but they are also vulnerable to weather and environment. Laser weapon has a history of more than 30 years, and its key technology has also made a breakthrough. The United States, Russia, France, Israel and other countries have successfully carried out various laser shooting experiments. At present, low-energy laser weapons have been put into use, mainly used for short-range interference and blinding photoelectric sensors, as well as attacking human eyes and some enhanced observation equipment; High-energy laser weapons mainly use chemical lasers. According to the current level, it is expected to be deployed and used on ground and air platforms in the next 5- 10 years for tactical air defense, theater anti-missile and anti-satellite operations.
Other characteristics of laser:
Laser has many characteristics: first, laser is monochromatic, or single frequency. Some lasers can produce lasers with different frequencies at the same time, but these lasers are isolated from each other and used separately. Secondly, the laser is coherent light. The characteristic of coherent light is that all its light waves are synchronous, and the whole beam of light is like a "wave train". Thirdly, laser is highly concentrated, that is, it needs a long distance to disperse or converge.
Laser is a kind of light source invented in 1960s. Laser is the abbreviation of stimulated emission amplification in English. There are many kinds of lasers, ranging in size from several football fields to a grain of rice or salt. Gas lasers include He-Ne lasers and argon lasers; Solid-state lasers include ruby lasers; Semiconductor lasers have laser diodes, such as CD players, DVD players and laser diodes in CD-ROMs. Each laser has its own unique method of generating laser.