Popularization of Laser Technology and Application Analysis

Preface: Speaking of laser, people are not familiar with it, the application of laser in life should have heard of many kinds, such as myopia laser correction, laser beauty and so on. In addition to medical applications, the laser is also used in industrial, scientific research, information and military fields. Want to learn more about the laser in the environment detection and defense applications, let the Xi'an University of Science and Technology Laser Radar Atmospheric Remote Sensing Research Center Dr. Huayin Xin to tell you.

What is a laser?

Laser is the use of light energy, heat, electricity, chemical energy or nuclear energy and other external energy to stimulate the material, so that the occurrence of stimulated radiation generated by a special light. The laser is the stimulated radiation of light. Compared with ordinary light source, the characteristics of the laser are obvious, the direction is good (divergence angle is small), the searchlight is irradiated to the moon, the parallel searchlight 1 km when the spot diameter of 10 meters, the laser irradiation of the moon, spot diameter is about 2 km. High brightness, good color (color purity), good coherence, the speed of light transmission (3 × 108m / s) and so are the characteristics of the laser.

The phenomenon of light in nature is ubiquitous, and the understanding of light has experienced a complex process of evolution, and today it is not yet over. In particular, the appearance of the laser has changed people's awareness of light. In 1960, the American physicist Mehman developed the first ruby lasers, to bring a revolution to the optical, greatly promoted the optical and related scientific development.

2 laser technology development

As a carrier of modern information transmission, light has played a great role in modern science. The Nobel Prize for Physics also certainly optics in modern development. From 1997 laser cooling, 2000 semiconductor lasers, 2005 quantum optical precision measurement technology, to 2009 fiber optic communication CCD. Laser technology advances brought about by the great social change, get the community and people recognized.

In 2009, Chinese expert Gao Kun won the Nobel Prize in Physics, which began in 1957 in the field of optical fiber applications in the field of communications research, published in 1966, entitled "light frequency dielectric fiber surface waveguide" papers, groundbreaking The basic principle of optical fiber application in communication is proposed. In 1981 the first optical fiber system available. Since then, the use of quartz glass made of fiber applications more and more widely, the world set off a revolution in optical fiber communications. Since then, than the human hair but also fine fiber to replace the huge volume of millions of copper wire, as a huge transmission capacity of the information transmission pipeline, completely changed the human communication model. Optical fiber as a light carrier and sensor devices, the development of its technology and its application, are dependent on the progress of laser technology. With the development of optical, especially the progress of laser and optoelectronic technology, people have a deeper understanding of light and application, optical has been deep into the medical, geological, aerospace, military, entertainment and other social fields.

3 laser with fiber is a pair of twin brothers

The peak power of the laser is large and can reach several hundred thousand megawatts because of its large energy can be used as laser cutting, laser medical, laser weapons. In addition, laser applications are laser ranging, laser gyro, laser processing. Laser medicine, the most simple application is the teeth, teeth when the sound, each patient are reluctant to listen, but if you use the laser to fill teeth, you can use the laser surface tartar, insect teeth part cut off, no sound. Laser processing, to make a rough part of the hair to do a gear, hair only 50 microns, in this to do a flat gear, the general mechanical means is not reach, can only use the laser.

Fiber laser has changed people's lives, each Internet access is transmitted by the fiber, so now you can contact with the rest of the world. Fiber as the carrier of light, its application development should rely on the laser, the fiber is not the current sink, is the light, the light is the laser. Now the optical fiber communication, optical fiber transmission is much faster than the previous electromagnetic wave communication, because the light propagation speed, the speed of 300,000 kilometers per second in the transmission. Give a simple example, the early 90s of last century, call back from abroad, the microphone can hear their own echo, but now as long as the phone in hand, hit the world every corner is very clear.

Optical fiber sensing technology can be buildings, bridges and other large building deformation, as well as large substation temperature changes in real-time precision detection. How to use optical fiber measured large buildings have not deformed it? In the construction process, the fiber embedded in concrete, the path is equivalent to blood vessels, through the fiber to the laser into, through a certain sensor technology to know where there is a trace of deformation, you can immediately detect it. Foreign skyscrapers, floor of the base are buried with fiber optic sensors, the fiber directly poured into the cement column, you can real-time monitoring of cement column deformation. This is the application of laser plus fiber.

In addition, the use of multi-fiber made of fiber optic cable has been paved the world, as the Internet, the cornerstone of the global communications network; fiber in medicine has also been widely used, such as endoscopy and other endoscopes can allow doctors to see the patient's body ; Fiber optic sensing technology and systems are also a large number of industrial applications, in all types of manufacturing and mechanical processing, and so on.

4 laser in the application of aerospace

Air space development, the use of laser can not be underestimated. In the lunar exploration project, Chang'e to the moon to get the first three-dimensional map of the moon, this time to use the laser, with laser for ranging, get a very high gradient of the moon, for the next step to make a contribution to the moon. Rabbit to land on the moon, landing on the surface of the moon platform has a laser measuring the distance between the lander and the lunar surface, which landed smoothly.

With the rapid development of information, many need to use the network. Last year, China launched the "Mozi" satellite, which is China's first, but also the world's first heaven's quantum satellites. Some people will certainly ask, quantum and laser what is the relationship? "Quantum communication refers to the use of quantum entanglement effects for information transmission of a new type of communication, with high efficiency and absolute security, etc. However, all quantum communication networks must use laser technology," said Dr. Huayin Xin. Quantum is the smallest unit capable of exhibiting a substance or physical property. The "quantum of light" (photon) is the basic energy unit of light at a certain frequency. Compared with the light quantum communication, the classical communication can not be compared with the security and the high efficiency. Security - quantum communication will never "leak", and its integration is now quantum encryption key is random, even if the stealers intercepted, can not get the correct key, it can not break the information; Second, respectively, in the communication Two quantum particles with entangled states in which the quantum state of one particle changes and the other quantum state changes immediately, and any quantum observation and interference according to quantum theory will immediately change the quantum state and cause it Collapsed, so the theft of information due to interference has been destroyed, not the original information. Therefore, quantum communication can achieve absolute confidentiality of communication.