There are many kinds of laser, such as solid, gas, liquid, semiconductor, dyeslaser, etc..
(1) Solid state laser is generally small and rugged, and high power of pulse radiation. The application range is wide. Nd: YAG laser is one of solid-state laser. Nd(nd) is a kind of rare earth element, and YAG stands for yttrium aluminum garnet, whose the crystal structure is similar to that of ruby.
(2) Semiconductor laser has the advantages of small volume, light weight, long service life, simple structure, and is especially suitable for being used in aircraft, ships, vehicles and spacecraft.Semiconductor laser can change the wavelength of laser through the external electric field, magnetic field, temperature, pressure etc. And it can also directly convert the electric energy to laser energy, so the development is very rapid.
(3) Gas laser with gas as working substance, has good mono chrom activity and coherence, and the laser wavelength can be up to thousands of species.Gas laser has the advantages of simple structure, low cost and convenient operation.Gas laser is widely used in industrial and agricultural, medical, precision measurement, holographic technology, etc. Gas laser has a variety of incentives, such as electrical energy, heat energy, chemical energy, nuclear energy and so on.
(4) Dye laser, which is using liquid dyes as working substance, appeared in 1966, and it is widely used in various scientific research field. About 500kinds of dyes can be found, which are able to produce laser. These dyes are soluble in alcohol, benzene, acetone, water or some other solutions, and they can also be included in the organic plastic and appear in the form of solid, or gasstate, so dye laseris also called "liquid laser".The prominent characteristic of dye laser is adjustable wavelength. And dye laser is widely used in spectroscopy, photochemistry, medical and agricultural because of the characteristics of many kinds of fuel laser, low price, high efficiency, the output power that can be comparable with the gas and solid laser.
(5) Infrared laser has many types and wide range of application.It is a new type of infrared radiation source, which radiation characteristics are high strength, good monochromaticity, good coherence and strong direction.
(6) X ray laser has important value in scientific research and military, has the advantage of application in laser anti-missile weapon. A biologist can study the molecular structure of the living tissue and understandcell functions in detailby using X ray laser. The photos ofthe molecular structure was taken byX ray laser, which has high contrast.
(7) Some chemical reactions can produce high energy atomic enough and release a large energy, which can be used to produce chemical laser.
