Laser production and the new discipline of laser development

Source：China laser network   Time：2016-04-16   Edit：SunyLaser

1 what is laser
In English, the term "laser" is "LASER", which is the abbreviation of "Amplification by Stimu Iatad Emission of Radiation Light", which means "radiation light amplification by stimulated emission". In 1964, according to China's famous scientist Tsien Hsueshen proposed that "stimulated emission of light" was renamed "laser".
The laser is a new light source, which is produced by the laser. Since twentieth Century, after the atomic energy, computer, semiconductor, another major invention. Laser is emerged under the background of the urgent need of theory and practice, it came, unusually rapid development, the development of laser not only makes old optical science and optical technology gained a new life, but also lead to the emergence of the emerging industries. Laser can make people use unprecedented advanced methods and means to achieve unprecedented benefits and results, thus promoting the development of productive forces.
So, what is the laser in the end? Let's get to know something about it! Although the laser light with the word, however, it is very different from ordinary light. So, what is the difference between a laser and an ordinary light?
First, the laser is one of the most simple colors of light. The sun light and electric light appears to be white, but when let it through a prism, you can see red, orange, yellow, green, blue, blue, purple, seven color light, in fact, also contains we see invisible infrared light and ultraviolet light. Laser color is very simple, and only to a direction of light, high brightness.
Second, the direction of the laser is good. In the emission direction of the space of light energy concentration, so the brightness of the laser light than ordinary light, and even hundreds of millions of times. And because you can control the laser, optical energy not only in highly concentrated, and in time is highly concentrated, and in a flash produced great light and heat, has become invincible can be powerful beam. At ordinary times, we see the lights are light in all directions, is like the cinema afterwards, everyone back and forth towards all directions to cutting come out. Turn on the light in the room, the whole room is lit up. Again, open the flashlight, in the issue of the site, the diameter of 3 ~ 5 cm, to be shot to a few meters away, it expanded into a large aperture. This shows that the light in the spread of the spread.
However, the laser is different, it is a large number of atoms due to the stimulated emission of light emitting behavior. Laser in the spread is always like a straight line, the divergence angle is very small, a beam of laser shot to 380 thousand kilometers outside the moon, the aperture diameter is only about 2 kilometers. Is the cinema afterwards like, everyone lined up to toward a direction, stepping the pace of the same size, with the "one, two, one" password, neatly forward.
Third, the highest brightness of the laser. The sun is a common natural light source, the whole world is bathed in bright sunlight. The brightness of the sun's surface is 300 thousand times larger than that of the candle, which is several hundred times larger than that of the incandescent lamp. The appearance of the laser, it is a spectacular leap in the brightness of the light source.
The output brightness of an ordinary laser is 1 billion times larger than that of the surface of the sun. It is not a problem to be reflected back from the earth to the moon. Visible light is a high brightness light source in the world today.
Fourth, the laser can also have a lot of energy, it can easily be used to make holes in the steel plate or cut. In industrial production, laser drilling, cutting and welding have been successfully carried out by using the characteristics of high brightness of laser. In medicine, the use of high energy laser can be stripped of retinal coagulation and surgery. In terms of Surveying and mapping, the distance between the earth and the moon can be measured. In the military field, the laser energy increases, can be made into light weapons to destroy enemy aircraft and missiles.


     Two. New disciplines developed by laser
The emergence of laser led to the development of many disciplines, such as quantum optics, quantum electronics, laser spectroscopy, nonlinear optics, integrated optics, ocean optics and so on. Here we only list some of the daily life related to the development of laser applied science.

(1) laser disc making technology

In 1877 the world's first phonograph was born in the hands of Edison! It is the beginning of the development of audio and video technology. People are not satisfied with the player, 40 in the early 20th century, Germany developed with high frequency partial magnetic and good mechanical transmission performance of the tape recorder, open up new channels of sound recording. By 1955, the Radio Corporation of America announced color the tape recorder, able to record himself and nature image. It opens the new page in the history of the audio-visual technology, open the doors and pathway of modern audio-visual technology development. 3 years later, the United States Anpike company to produce a commercial color video recorder. In 1970, the British Decca company developed the first black and white TV video disc. Two years later, Philip, Holland, developed a color television footage of the laser pickup. This is the birth of the modern laser disc!
The birth of the laser disc, the application of the laser on the sound equipment, is a revolution on the sound. People use a laser to "light" to replace the needle, needle made of stones, cd. Laser recording can not only record, but also be able to record. Laser record used to record, store image and sound, it can be said, this is a revolution in the audio-visual technology, a great pioneering work.
Since the laser disc people to fully tap the potential, to create multifunctional laser gramophone and records, in 1983, the United States and Japan were developed new digital recordings. This record completely free from the traditional record of the production and playback mode, for the record has opened up a new realm. This kind of digital record, in the storage technology and so on has the important use.
The development of laser disc technology soon, various functions and various uses of the new record player, emerge in an endless stream. Thus, the laser disc and electronic computer technology, audio-visual technology together, into the field of storage and retrieval of literature. Information is stored on an optical disc, which can quickly retrieve, consult, and print out the required information. Now CD books have entered the family life.

(2) vivid pictures

Modern holography, accompanied by laser technology and new development, provides us with a way to capture all the visible information of the scene, and can get a very realistic three-dimensional display of the hologram. In the light of an appropriate light, the original scene will be reproduced in our presence. As a result of holographic recording of all the information of the light wave of the scene, so the reconstructed scene and the original exactly the same. A hologram reproduced the scene is so lifelike that make people have a sense of immersive, that I wanted to go in for a closer look, want to stretch out a hand to touch. A hologram is a real stereo. Photographs obtained by holography can withstand the destructive blow". Holographic photos of each part, regardless of how much, can represent the whole picture of the original, that is to say, the hologram is divided into several blocks, each piece can be a full presentation of the original scene. So if the hologram is broken, tear up, or trapped in a case, the debris of a destroyed hologram can be reproduced from a scrap of scrap.
 
 (3) laser medicine

Laser medicine is a new field of laser technology, after the advent of the world in 1960 the first ruby laser, 1961 for the treatment of retinal detachment, 1963 laser scissors for cutting tumour. Medical laser treatment machine is widely used in clinical departments in 70. In 1981, the United Nations Health Organization officially announced a new branch of laser medicine.
People use different wavelengths and different dose laser test, in-depth study of the basic mechanism of photosynthesis of green plants, in-depth study from the basic process of until mature and produce seed germination. People take appropriate wavelengths and appropriate doses of laser irradiation is growing crops, promote the photosynthesis of crops, thereby improving the yield and quality of crops. For example, increase with laser irradiation of cucumber seedlings and tomato vines, the Yangzi flower number and fruit number, yield was increased, fruit in sugar and vitamin content increased, quality improved significantly.
The prevention and cure of crop diseases and insect pests were also studied by laser. Lasers become the right assistant to kill pests and pests and diseases. People use laser to remove weeds, weeds on seedlings to vent, to encourage the seedlings. The laser exterminator weeding method, than to take the superior chemical pest control, weeding, avoiding the chemical drugs to air, water and land pollution, and no pollution to crops, vegetables and fruits. The laser is an effective and clean weeding method of pest control.
Laser in agricultural and sideline products storage and preservation, in prediction and estimation and other aspects to harvest the crop, are useless. Laser in the realization of scientific farming and agricultural modernization, will play an increasingly important role.

(4) the application of laser in the environment (laser)

Using laser to draw disaster map. A laser range finder is emitting a beam of light on the safety of the human eye, in order to measure the distance and azimuth of the target. After the target is returned to the laser, the computer attached to the laser immediately carries out the necessary operation. If the laser range finder is connected to a global positioning system, the satellite receiver will tell the operator where it is located at any time. The system operator can aim the laser at the storm disaster, the laser will distance and range of information to the global positioning system, draw the disaster map, and then quickly send the relevant personnel to disaster relief. Another set of operating system connected with computer records, operation personnel can hover over the neighborhood, laser of Huai affected the buildings on the ground and quickly draw the map, estimated the value of the damaged property.
Laser atmospheric detection in content, using the Free University of Berlin, laser radar three-dimensional monitoring of urban smog and acid rain has been measured nitrous oxide, nitrogen dioxide, sulfur dioxide, and ozone content of the two-dimensional and three-dimensional map. The water vapor contour map of the planetary boundary layer above sea level 4km has been successfully applied to meet the needs of meteorological applications.