Essence of laser

   The electrons move randomly around the nucleus, but at different energy levels at different distances.When an electron drops from a high energy level to a low energy level, according to the law of conservation of energy, this part of the energy will be released in the form of light and heat, which is the nature of light.And light has wave-particle duality, different wavelengths of light show different characteristics, in line with a certain wavelength of light and show, is the laser.
 

Features:

   Directivity is good: the divergence Angle after the laser is very small, the laser shoots 20 kilometers, the spot diameter is only a few tens of centimeters, the laser shoots 380,000 kilometers to the moon, the spot diameter is less than 2 kilometers.

   Monochromatic sex is good: the color of light is decided by the different wavelength of light, different color, it is the difference that the light of different wavelength ACTS on the person's vision and reflect.The wavelength of laser is basically the same, the spectral line width is very narrow, the color is very pure.Monochrome is good.Because of this characteristic, laser is widely used in communication technology.

   High brightness: Due to its strong emission ability and high concentration of energy, the laser is very bright. It is billions of times higher than the ordinary light source and tens of billions of times brighter than the surface of the sun.Brightness is an important index to measure the quality of a light source. If the laser beam with moderate intensity is converged, it can produce high temperature of thousands to tens of thousands of degrees at the focal point.

   Good coherence: the coherence is a common feature of all waves, but due to the different quality of the various light waves, their coherence can also be high or low.Ordinary light radiates light spontaneously without interference.Laser is different from ordinary light source, it is stimulated radiation light, has extremely strong coherence, so called coherent light.
 

Species

   Lasers represent different colors at different wavelengths, and there are even invisible infrared lasers, as follows:

   The color wavelength of visible laser beam from short to long is in order: blue-violet (405nm), blue (445nm, 460nm, 473nm), green (532nm), yellow (589nm) and red (635nm, 650nm).

   Invisible infrared laser (808nm, 980nm, 1064nm) has a longer wavelength than visible red light.

   At present, the common lasers are divided into gas laser, solid laser, semiconductor laser, fiber laser and dye laser according to the working medium, and recently free electron laser has been developed.The high power laser usually pulsed output to obtain a large peak power.
 

Application

Laser communication:
   Laser is used for carrier communication. Due to its strong anti-interference, it has high transmission bandwidth, large capacity and long distance.

Laser medicine:
   Can play a variety of roles, such as drill, scalpel, welding gun, or laser surgical treatment, weak laser biological stimulation of non-surgical treatment and laser photodynamic therapy.

Laser ranging:
    Laser ranging takes the laser as the light source for ranging.Compared with the photoelectric rangefinder, it can not only operate day and night, but also improve the range accuracy, significantly reduce the weight and power consumption, so that the measurement of the distance to the man-made earth satellite, the moon and other distant targets become a reality.

Laser processing:
   Including cutting, welding, surface treatment, drilling, marking, marking, fine tuning and other processing technology.

Compact disc:
   Can be used to store all kinds of information and sound.DVDS can store and reproduce pictures and films, while computer-aided, fully functional CD-ROMs can contain a wide range of information, from words and music to pictures and live television footage.

Military lasers:
   Lasers have applications at both the attack and defense levels.