At the micro level, electrons move randomly around the nucleus, but the distance between the two is different at different energy levels. When electrons fall from a high energy level to a low energy level, according to the law of conservation of energy, this part of energy is released in both light and heat. This is the nature of light. Whereas light has wave-particle duality, different wavelengths of light show different characteristics, and it is a laser that is represented by a certain wavelength of light.
The wide range of applications of lasers depends on their characteristics:
● Good directionality: The divergence angle after laser firing is very small. The laser is ejected for 20 kilometers. The spot diameter is only a few tens of centimeters. The laser beam reaches the 380,000 kilometers of the moon and its spot diameter is less than 2 kilometers.
● Good monochromaticity: The color of light is determined by the different wavelengths of light. Different colors are reflected by different wavelengths of light acting on human vision. The wavelength of the laser is basically the same, the spectral line width is very narrow, and the color is very pure. Monochromaticity is good. Because of this feature, lasers are widely used in communications technology;
● High brightness: Due to the strong laser emission power and high concentration of energy, the brightness is very high. It is hundreds of millions of times higher than ordinary light sources and several billion times more bright than the surface of the sun. Brightness is an important index to measure the quality of a light source. If a medium-strength astronomy laser pointer beam is converged, it can produce several thousand to tens of thousands of degrees of heat at the focal point.
● Coherence is good: Coherence is the commonality of all waves, but due to the different qualities of various light waves, their coherence is also high and low. Ordinary light is spontaneously radiated without interference. Laser is different from ordinary light source, it is stimulated radiation, has a strong coherence, so called coherent light.
We usually see and our consciousness, the laser should be red. In fact, lasers represent different colors at different wavelengths, and even invisible infrared lasers, as follows:
● The wavelengths of the laser visible light beam from the shortest to the longest are: blue-violet (405nm), blue (445nm, 460nm, 473nm), green (532nm), yellow (589nm), and red (635nm, 650nm)
● Invisible infrared lasers (808nm, 980nm, 1064nm) have longer wavelengths than visible red light.
Here we talk about the types of lasers. At present, common lasers are divided into gas lasers, solid-state lasers, semiconductor lasers, fiber lasers, and dye lasers in working media. Recently, free-electron lasers have also been developed. High-power lasers usually pulse output to obtain larger peak power.
The use of laser:
● Laser communication: Using laser to carry out carrier communication, because of its strong anti-interference, so it has high transmission bandwidth, large capacity and long distance.
● Laser Medicine: Enough to play various roles such as drills, scalpels, welding guns, or laser surgery, non-surgical treatment of weak laser biostimulation, and photodynamic therapy of lasers.
● Laser distance measurement: Laser distance measurement uses laser as the light source for distance measurement. Compared with the photoelectric distance meter, it not only can work day and night, but also can improve the distance measurement accuracy, significantly reduce the weight and power consumption, and make the distance from the artificial satellite, the moon, and other distant targets measured into reality.
● Laser processing: including cutting, welding, surface treatment, drilling, marking, marking, fine-tuning and other processing techniques.
● Laser Record: Can be used to store various information and sounds. DVDs are capable of storing and reproducing images and movies. Computer-assisted, freely-operable CD-ROMs can accommodate all ranges of information, from words and music through to television footage of events and events.
● Military lasers: Lasers have applications at the attack and defense levels. In terms of attack, the United States has developed laser cannons and successfully tested it; in terms of defense, Lidar also has a wide range of uses.