2. Development:
Laser has the characteristics of good monochromaticity, strong directivity and high brightness. Thousands of laser working substances have been found, ranging in wavelength from soft X-ray to far infrared.
The core of laser technology is laser. There are many kinds of lasers, which are classified according to different methods such as working substance, excitation mode, working mode and working wavelength.
According to different application requirements, some special technologies are adopted to improve the beam quality and single technical index of the output laser. The widely used cell technologies include * * resonator design and mode selection, frequency doubling, tuning, Q-switching, mode locking, frequency stabilization and amplification technologies.
3. Principles:
Scientists use the energy of light or current to hit some excitable substances of crystals or atoms in electron tubes, so that the electrons of their atoms reach the excited high-energy state. When these electrons return to a calm low-energy state, atoms will emit photons and release excess energy. Then, these released photons will hit other atoms, exciting more atoms to produce photons, triggering a series of "chain reactions", which all move in the same direction, forming a strong and concentrated light in a certain direction; Therefore, intense laser can even be used to cut steel plates!
4. Features:
Laser is widely used because of its characteristics. (Monochromatic wavelength, coherence, parallel beam)
Laser is almost a monochromatic light wave with a narrow frequency range, which can concentrate high energy in a narrow direction, so the focused laser beam can be used to punch holes in various materials. Take ruby laser as an example, the total energy of its output pulse is not enough to boil an egg, but it can make a small hole in a 3mm steel plate.
Laser has the above characteristics, not because its light energy is different from other light, but because of its high power density, which is also the reason why laser is widely used.
Extended data:
Development of Early Laser Technology in China
From 65438 to 0957, Wang Daheng and others established the first optical professional research institute in China-Institute of Optical Precision Instruments and Machinery of China Academy of Sciences (Changchun) (referred to as "Institute of Optics and Mechanics"). Under the leadership of the older generation of experts, a group of young scientific and technological workers have grown up rapidly, and Deng is one of the outstanding representatives. As early as 1958, shortly after the publication of the famous papers on laser principle by American physicists Luo Xiao and Downs, he actively advocated the research of this new technology, and in a short time, he gathered innovative young and middle-aged research teams and put forward a lot of ideas and experimental schemes to improve the brightness, unit color and coherence of light sources.
1960 The world's first laser came out. 196 1 In the summer of, under the auspices of Wang Zhijiang, the first ruby laser in China was successfully developed. In just a few years, laser technology developed rapidly and produced a number of advanced achievements. Various types of solid, gas, semiconductor and chemical lasers have been successfully developed. In basic research and key technologies, a series of new concepts, methods and technologies (such as Q-mutation of cavity and Q-switch of rotating mirror, traveling wave amplification, utilization of rhenium ions, free electron oscillation radiation, etc.). ) have been put forward and implemented, and many of them are original.
At the same time, laser, as a new light source with high brightness, high directivity and high quality, has been rapidly applied in various technical fields, showing strong vitality and competitiveness. In terms of communication, TV images were transmitted by laser demonstration in September, and 3-30 km calls were realized in 1964 and1October. In industry, the laser drilling machine was successfully used in the stamping production of wire drawing dies from May 65438 to May 0965, and achieved remarkable economic benefits. In medicine, from June 65438 to June 0965, animal and clinical experiments were carried out with laser retina welding machine. In national defense, 1965 successfully developed a laser diffuse reflection rangefinder (accuracy 10 m/10 km), and 1966 successfully developed a remote-controlled pulsed laser Doppler velocimeter.
It can be said that in the initial stage, China's laser technology developed rapidly, both in quantity and quality, which were close to the international level at that time. It is rare for an innovative technology to catch up with the world's advanced ranks so quickly in the history of modern science and technology development in China. These achievements, especially the smooth transformation of physical ideas and technical schemes into practical laser devices, mainly benefit from the comprehensive ability and solid foundation accumulated by the Institute of Optics and Mechanics in technical optics, precision machinery and electronic technology for many years. The development of a new technology, without sufficient technical support, is difficult to form a climate.
Since 196 1 announced the successful development of China's first laser, with the joint efforts of laser research, teaching, production and use units across the country, China has formed a laser science and technology field with complete categories, advanced level and wide application, and made gratifying progress in industrialization, which has made positive contributions to China's science and technology, national economy and national defense construction and won a place in the world.
Baidu encyclopedia-laser technology
Baidu encyclopedia-? History of Modern Optics and Photoelectricity in China