Innovative and unique designs such as cylindrical lens array docking with two targets, multi-target series connection, two-way amplification and long-distance multi-target series space beam limitation are creatively adopted, and a series of effective technical means for accurate adjustment of targets and X-ray mirrors and accurate collimation of focal lines are established. The soft X-ray laser output with gain saturation intensity and directivity close to the diffraction limit was successfully obtained in a series of neon-like germanium experiments on the medium-sized Shen Guang I facility. Then, a Ni-like ion soft X-ray laser with a wavelength near the water window was obtained by creatively adopting the focal line overlapping scheme on the larger Shen Guang Ⅱ facility, which was driven by the pre-main pulse laser. Two rounds of cooperative experiments were carried out in gekko? facility of the Institute of Laser Engineering of Osaka University in Japan. The technology of uniform line focusing and double target docking has been successfully popularized, and the output of high-intensity nickel-like ion soft X-ray laser has been obtained.

Application of laser technology

Laser machining technology is a technology that uses the characteristics of the interaction between laser beam and substance, and takes cutting, welding, surface treatment, drilling, micromachining materials and identifying objects as light sources. The most traditional application field is laser processing technology. Laser technology is a comprehensive technology involving optics, mechanics, electricity, materials, detection and other disciplines. Traditionally, its research scope can be generally divided into:

Laser processing system. Comprise a laser, a light guide system, a processing machine tool, a control system and a detection system.

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

Laser welding: automobile body thick plates, automobile parts, lithium batteries, pacemakers, sealed relays and other sealing devices, as well as various devices that are not allowed to weld pollution and deformation. At present, the lasers used are YAG laser, CO2 laser and semiconductor pump laser.

Laser cutting: cutting all kinds of metal parts and special materials in automobile industry, computer, electrical cabinet and woodworking tool mould industry, circular saw blade, acrylic, spring washer, copper plate of electronic parts below 2mm, partial metal mesh plate, steel pipe, tinned iron plate, lead-plated steel plate, phosphor bronze, bakelite plate, thin aluminum alloy, timely glass, silicone rubber and alumina ceramic plate 1mm or less. The lasers used are YAG laser and CO2 laser.

Laser marking: widely used in various materials and almost all industries. At present, the lasers used are YAG laser, CO2 laser and semiconductor pump laser.

Laser drilling: Laser drilling is mainly used in aerospace, automobile manufacturing, electronic instruments, chemical industry and other industries. The rapid development of laser drilling is mainly reflected in the increase of the average output power of YAG laser for drilling from 400w five years ago to 800w, reaching1000 W. At present, the more mature application of laser drilling in China is in the production of synthetic diamond and natural diamond wire drawing dies, as well as the production of gem bearings in industries such as clock instruments, aircraft blades and multilayer printed circuit boards. At present, most of the lasers used are YAG lasers and CO2 lasers, but there are also some excimer lasers, isotope lasers and semiconductor pump lasers.

Laser heat treatment: widely used in automobile industry, such as heat treatment of cylinder liner, crankshaft, piston ring, commutator, gear and other parts, as well as aerospace, machine tool industry and other mechanical industries. Laser heat treatment is widely used in China than abroad. At present, most of the lasers used are YAG laser and CO2 laser.

Laser rapid prototyping: it is formed by combining laser processing technology with computer numerical control technology and flexible manufacturing technology. Mostly used in mold and model industry. At present, most of the lasers used are YAG laser and CO2 laser.

Laser coating: widely used in aerospace, mold and electromechanical industries. At present, most of the lasers used are high-power YAG lasers and CO2 lasers.

Application of laser in medicine

Laser system applied to dentistry

According to the different functions of laser in dental application, it can be divided into several different laser systems. An important feature of distinguishing lasers is that the wavelength of light has different effects on tissues. Visible light and near infrared spectrum have low light absorption rate and strong penetration, and can penetrate deep tooth tissues, such as argon ion laser, diode laser or Nd: YAG laser (as shown in figure 1). However, Er: YAG laser and CO laser have poor light penetration, which can only penetrate the tooth tissue by about 0.01mm.. The second important feature that distinguishes laser is the intensity (i.e. power) of laser. For example, diode laser used for diagnosis is only a few milliwatts, and sometimes it can also be used for laser display.

The laser used for treatment is usually a moderate intensity laser of several watts. The effect of laser on tissue also depends on the way of laser pulse emission. Typical continuous pulse emission methods are argon ion laser, diode laser, CO2 laser and laser. Some Er: YAG lasers or many Nd: YAG lasers emit in short pulses. The intensity (i.e. power) of short-pulse laser can reach more than 1 1,000 watts. These high intensity and high light absorption lasers are only suitable for removing hard tissues.

Application of laser in the diagnosis of dental caries

1. Demineralization and shallow caries

2. Recessive dental caries

Application of laser in treatment

1. Cut

2. Filler polymerization and pit treatment

Laser cosmetic surgery

(1) Laser is widely used in beauty industry. Laser produces monochromatic light with high energy, accurate focus and certain penetrating power, which acts on human tissues to produce high fever, thus cutting or destroying target tissues. Pulsed laser with different wavelengths can treat various vascular dermatoses and pigmentation, such as nevus OTA, nevus flammeus, freckles, senile plaque, telangiectasia, tattoo removal, eyeliner washing, eyebrow washing and scar treatment. In recent years, some new laser instruments, such as high-energy ultra-pulse CO2 laser, erbium laser, etc., have achieved good results in wrinkle removal, peeling and skin replacement, snoring treatment, tooth whitening and so on, which has opened up more and more broad fields for laser surgery.

(2) Laser surgery has incomparable advantages over traditional surgery. First of all, laser surgery does not require hospitalization, with small incision, no bleeding during operation, light trauma and no scars. For example, the traditional surgical treatment of bags under the eyes has many shortcomings, such as wide peeling range, more bleeding during operation, slow healing after operation and easy scarring. The application of high-energy ultra-pulse CO2 laser in the treatment of eye bags has the advantages of no bleeding, no suture, no influence on normal work, light edema at the surgical site, quick recovery and no scar left, which is incomparable to traditional surgery. Some endoscopic operations that cannot be performed due to excessive bleeding can be completed by laser cutting instead. (Note: There is a certain range of adaptation)

(3) Laser has achieved remarkable results in the treatment of vascular dermatosis and pigmentation. The treatment of port wine nevus with pulsed dye laser has obvious curative effect, little damage to surrounding tissues and almost no scar. Its appearance has become a revolution in the history of treatment of port wine stains, because in the history of treatment of port wine stains, radiation, freezing, electrocautery, surgery and other methods have a high incidence of scars, and pigment loss or deposition often occurs. Laser treatment of vascular dermatosis is the selective absorption of oxygen-containing hemoglobin to a certain wavelength of laser, which leads to the high destruction of vascular tissue. It has high accuracy and safety, and will not affect the surrounding adjacent organizations. Therefore, laser treatment of telangiectasia is also effective.

In addition, due to the appearance of variable pulse laser, great breakthroughs have been made in removing unsatisfactory tattoos and treating various pigmented skin diseases such as OTA nevus and senile plaques. According to the theory of selective photothermal effect (that is, lasers with different wavelengths can selectively act on skin lesions of different colors), this kind of laser uses its powerful instantaneous power, highly concentrated radiation energy, pigment selectivity and extremely short pulse width to concentrate laser energy on pigment particles, vaporize and crush them directly, and excrete them through lymphatic tissues, without affecting the surrounding normal tissues. It is deeply rooted in people's hearts because of its exact curative effect, safety and reliability, no scar and little pain.

(4) Laser surgery initiated a new era of medical beauty. High-energy ultra-pulse CO2 laser peeling and skin changing has opened up a new technology in cosmetic surgery. It uses high-energy, ultra-short pulse laser to vaporize the damaged skin tissue instantly, without damaging the surrounding tissues, with almost no bleeding during the treatment, and can accurately control the depth of action. Its effect has been fully affirmed by the international medical plastic surgery field, and it is known as "creating a new era of medical beauty"; In addition, there is a high-energy ultra-pulse CO2 laser instrument to treat bags under the eyes, snoring, and even laser whitening teeth. With its safe and accurate curative effect and simple and quick treatment, it has created one miracle after another in the field of medical beauty. Laser cosmetology has made medical cosmetology take a big step forward and given the connotation of medical cosmetology renewal.

Laser cooling

Laser cooling is to use the interaction between laser and atoms to slow down the motion of atoms, so as to obtain ultra-low temperature atoms. In the early days, the main purpose of this important technology was to accurately measure various atomic parameters for high-resolution laser spectrum and ultra-high-precision quantum frequency standard (atomic clock), but later it became the key experimental method to realize atomic Bose-Einstein condensation. Although people noticed that light had radiation pressure on atoms as early as the beginning of the 20th century, it was not until the invention of laser that the technology of changing the speed of atoms by using light pressure was developed. It is found that when an atom moves in a pair of laser beams with a frequency slightly lower than the energy level difference of the atomic transition and propagating in opposite directions, due to the Doppler effect, the atom tends to absorb photons in the opposite direction to the atom, but the probability of absorbing photons propagating in the same direction is small. The absorbed photons will spontaneously radiate isotropically. On average, the net effect of two lasers is to produce a damping force opposite to the direction of atomic motion, thus slowing down the movement of atoms (that is, cooling down). 1985, Phillips of the National Institute of Standards and Technology and Steven Chu of Stanford University first realized the experiment of laser cooling atoms, and obtained extremely low temperature (24μK) sodium gas. They further used a three-dimensional laser beam to form magneto-optical theory, trapped atoms in a small area of space and cooled them, and obtained "optical viscose" with lower temperature. Since then, many new laser cooling methods have appeared. Among them, the most famous ones are "velocity selective coherent population limitation" and "Raman cooling". The former was put forward by Claude Cohen-Tannoji of Paris Teachers College, while the latter was put forward by Zhu. They used this technology to obtain extremely low temperatures below the photon recoil limit. Since then, people have developed a series of cooling technologies combining magnetic field and laser, including polarization gradient cooling and magnetic induction cooling. Zhu, Cohen Danoki and Phillips also won the 1997 Nobel Prize in Physics. Laser cooling has many applications, such as atomic optics, atomic etching, atomic clock, optical lattice, optical tweezers, Bose-Einstein condensation, atomic laser, high-resolution spectroscopy, and basic research on the interaction between light and matter.

Laser spectrum

Laser spectroscopy is a spectral technology with laser as light source. Compared with ordinary light sources, laser light source has the characteristics of good monochromaticity, high brightness, strong directivity and strong coherence, and is an ideal light source to study the interaction between light and matter, so as to identify the structure, composition, state and change of matter and its system. The appearance of laser greatly improves the sensitivity and resolution of the original spectral technology. Because of the extremely high intensity and narrow pulse width of laser, it is possible to observe the multiphoton process, nonlinear photochemical process and relaxation process of molecules after excitation, and they have developed into new spectral technologies respectively. Laser spectroscopy has become a research field closely related to physics, chemistry, biology and materials science.

Laser sensor

Laser sensor is a kind of sensor that uses laser technology to measure. It consists of a laser, a laser detector and a measuring circuit. Laser sensor is a new type of measuring instrument, which has the advantages of non-contact long-distance measurement, high speed, high precision, large measuring range and strong anti-photoelectric interference ability.

laser radar

Lidar refers to a radar that uses laser as a radiation source. Lidar is a combination of laser technology and radar technology. It consists of transmitter, antenna, receiver, tracking frame and information processing. Emitters are various types of lasers, such as carbon dioxide lasers, Nd-doped yttrium aluminum garnet lasers, semiconductor lasers and solid-state lasers with adjustable wavelengths. The antenna is an optical telescope; The receiver adopts various forms of photodetectors, such as photomultiplier tubes, semiconductor photodiodes, avalanche photodiodes, infrared and visible light multi-detector devices, etc. Lidar works in two modes: pulse or continuous wave. Detection methods are divided into direct detection and heterodyne detection.

Laser beam weapon

Laser weapon is a kind of directional energy weapon, which directly destroys or paralyzes the target by using directional laser beam. According to different operational purposes, laser weapons can be divided into tactical laser weapons and strategic laser weapons. The weapon system is mainly composed of laser, tracking, aiming and launching devices. At present, the commonly used lasers are chemical lasers, solid-state lasers and CO2 lasers. Laser weapons have the advantages of fast attack speed, flexible steering, accurate attack and no electromagnetic interference, but they are also vulnerable to weather and environment. Laser weapon has a history of more than 30 years, and its key technology has also made a breakthrough. The United States, Russia, France, Israel and other countries have successfully carried out various laser shooting experiments. At present, low-energy laser weapons have been put into use, mainly used for short-range interference and blinding photoelectric sensors, as well as attacking human eyes and some enhanced observation equipment; High-energy laser weapons mainly use chemical lasers. According to the current level, it is expected to be deployed and used on ground and air platforms in the next 5- 10 years for tactical air defense, theater anti-missile and anti-satellite operations.

Classification of laser weapons

Lasers with different power densities, different output waveforms and different wavelengths will have different destructive effects when interacting with different target materials. Using laser as a "dead light" weapon can't be focused through a lens like laser processing, but the output power of laser must be greatly improved, and suitable laser can be selected according to different needs in combat. At present, there are many kinds of lasers with different names, including lasers that occupy a whole building and have a power of trillions of watts, and semiconductor lasers that are smaller than human nails and have an output power of only a few milliwatts and are used for photoelectric communication. According to the working medium, there are solid-state lasers, liquid lasers and molecular, ionic and excimer gas lasers. At the same time, it can be divided into space-based, land-based and ship-borne according to its launch position. Vehicle-mounted and airborne types can also be divided into tactical and strategic types according to their uses.

1. Tactical laser weapon

Tactical laser warfare uses laser as energy, directly killing enemy personnel and destroying tanks and planes. Like conventional weapons, the strike distance can generally reach 20 kilometers. The main representatives of this weapon are laser guns and laser cannons, which can emit powerful laser beams to attack the enemy. 1978 In March, the world's first laser gun was born in the United States. The style of laser gun is not much different from that of ordinary rifle, and it mainly consists of four parts: laser, exciter, trigger and stock. At present, there is a ruby pocket laser gun abroad, which is about the same size as the Parker pen in the United States. However, it can burn clothes and flesh at a distance of meters, and it is silent, causing death and death unconsciously, and it can also make gunpowder explode within a certain distance, making photoelectric equipment such as night vision devices, infrared rays or laser rangefinders ineffective. There are also seven kinds of small laser guns, the weight of which is slightly larger than that of machine guns, which can penetrate the bronze helmet and burn the skin and flesh at a distance of 1500 meters, causing blindness.

The "gouging out" of tactical laser weapons will not only lead to the loss of control of aircraft, the destruction of aircraft or the loss of combat capability of machine gunners, but also the soldiers who participate in the war often bear heavy psychological pressure because they don't know when and where the opposing laser weapons will appear. Therefore, laser weapons have a deterrent effect that conventional weapons do not have. 1982 during the war on the British island of Oman, Britain installed laser blinding weapons on aircraft carriers and various frigates, which caused many Argentine planes to lose control, crash or mistakenly enter the British shooting net.

2. Strategic laser weapons

Strategic laser weapons can attack intercontinental missiles thousands of kilometers away; It can attack reconnaissance satellites and communication satellites in space. For example, in 1975 and 165438+ 10, two reconnaissance satellites in the United States, which were monitoring missile silos, were hit by land-based laser weapons of the former Soviet Union and became blind. Therefore, high-base and high-energy laser weapon is one of the ideal weapons to seize the superiority in space, and it is also the fundamental reason why military powers spend huge sums of money to compete fiercely. According to foreign journals, since 1970s, the United States and Russia have conducted dozens of anti-satellite laser weapon tests in various names.

At present, the types of anti-strategic missile laser weapons are chemical laser, excimer laser, free electron laser and beam modulation laser. For example, a free electron laser has the advantages of high output power, good beam quality, high conversion efficiency and wide adjustable range. However, the free electron laser is huge, and it is only suitable to be installed on the ground for land-based laser weapons. In the battle, the intense laser beam first hits the interrupt mirror in high orbit in space. The interrupt mirror reflects the laser beam to the low-orbit combat mirror, and then the combat mirror aims the laser beam at the target to attack. Through these two kinds of reflections, free electron laser weapons set on the ground can attack strategic missiles launched from anywhere in the world.

High-base high-energy laser weapon is the product of the combination of high-energy laser weapon and spacecraft. When this kind of laser swims along the orbit of space, it can be put into battle once it finds the other target. Because it is deployed in space, it is condescending and has a broad vision, which is even more powerful. In actual combat, it can be used to carry out lightning attacks on the air targets of the other side, thus destroying the reconnaissance satellites, early warning satellites, communication satellites and meteorological satellites of the other side, and even destroying the intercontinental missiles of the other side in the boosting and rising stage.

Laser glass

Laser glass is a solid laser material based on glass. It is widely used in various types of solid-state laser optical devices and has become the main laser material for high-power and high-energy lasers.

Laser glass consists of matrix glass and activating ions. Various physical and chemical properties of laser glass are mainly determined by matrix glass, while its spectral properties are mainly determined by activated ions. However, the matrix glass interacts with the activating ions, so the activating ions have a certain influence on the physical and chemical properties of the laser glass, and the influence of the matrix glass on its spectral properties is sometimes quite important.

Laser history

1958, American scientists Luo Xiao and Downs discovered a magical phenomenon: when they shine the light from the inner bulb on the rare earth crystal, the molecules of the crystal will emit bright light, and these lights will always gather together. According to this phenomenon, they put forward the "laser principle", that is, when a substance is excited by the same energy as its molecular natural oscillation frequency, it will produce this indiscriminate strong light-laser. They found important documents for this.

After the publication of the research results of Xiao Luo and Downs, scientists from all over the world put forward various experimental schemes, but none of them succeeded. 1960 on may 15, a scientist at Hughes laboratory in California announced that he had obtained a laser with a wavelength of 0.6943 micron, which was the first laser ever obtained by mankind, and thus became the first scientist in the world to introduce laser into practical fields.

1960 On July 7th, Mayman announced the birth of the world's first laser. Meman's plan is to use a high-intensity flash tube to excite the chromium atoms in the ruby crystal, thus producing a fairly concentrated slender red beam, which can reach a higher temperature than the surface of the sun when it hits a certain point.

Former Soviet scientist H.γ. Basov invented the semiconductor laser in 1960. The structure of semiconductor laser is usually composed of P layer, N layer and active layer, forming a double heterojunction. Its characteristics are: small volume, high coupling efficiency, fast response, wavelength and size suitable for fiber size, direct modulation and good coherence.

The new progress of laser research in China is of great significance to military science.

According to the Chinese Academy of Sciences, through the efforts of the R&D team of the Institute of Physics of the Chinese Academy of Sciences, the direct measurement of large-area excimer laser energy has been realized for the first time, and the effective measurement diameter is 100mm, which is the largest pyroelectric laser detector in the world at present. The cooperation with experts from China Institute of Atomic Energy and the experiments in the national laboratory show that the system has reached the expected technical indicators in different energy regions (10-20J and 100-200mJ).

According to reports, laser fusion research is a promising energy development topic, and laser-controlled thermonuclear fusion reaction will surely bring a new turning point to human life. Laser fusion is also of great significance in military scientific research. In the laser fusion experiment, especially in the research of indirect drive fusion, people pursue high X-ray conversion efficiency, good radiation transport environment and the best radiation driving field to produce strong radiation driving field. It is very important to directly monitor and study the energy of excimer laser in these research processes.

The research results show that the research and development of this project not only has the strength to continuously explore the developed product market, but also has the ability to undertake and develop the application demand projects being developed by the country.

The "laser revolution" is of great significance.

In modern society, information plays an increasingly important role. The faster, more accurate and richer the information, the more active the initiative and the more chances of success. The appearance of laser triggered an information revolution. From VCD and DVD discs to laser phototypesetting, the use of laser greatly improves efficiency and facilitates people to save and extract information. The "laser revolution" is of great significance. Laser has good space control and time control, and has great freedom for the material, shape, size and processing environment of the processed object, which is especially suitable for automatic processing. The combination of laser processing system and computer numerical control technology can form efficient automatic processing equipment, become the key technology for enterprises to implement timely production, and open up broad prospects for high-quality, efficient and low-cost processing and production. At present, laser technology has been integrated into our daily life, and in the years to come, laser will bring us more miracles.

Laser is a new modern light source, which has the characteristics of good directivity, high brightness and good monochromaticity. It is widely used, such as laser ranging, laser drilling and cutting, earthquake monitoring, laser surgery, laser singing head and so on. The unique ablation effect, shock wave effect and radiation effect produced by laser weapons have been widely used in air defense, anti-tank and bomber, and have shown their magical power. There are two leading companies in China's laser industry, Hanzu Laser in the south and G Keda (600986) in the north. Interestingly, the circulation of these two laser stocks is only 54.68 million shares and 49.53 million shares respectively, both of which are pocket-sized, but the share price of G University of Science and Technology is not as small as that of Hanzu Laser, so it has strong explosive potential in the future. G Kodak's main business is laser electronic products. The company cooperates with foreign capital to produce laser heads and related electronic products with international advanced technology level. The company has installed and operated 24 production lines, producing three types and multiple models of laser heads, and can process 48 million pieces of various laser heads every year, becoming the largest laser head production base in China and competing with the "big laser family" in the industry. Dongying Keying Laser Electronics Co., Ltd., a holding subsidiary of G Keda, is engaged in the production and sales of electronic laser heads, movements and related products. The leading product, digital decoding laser head, is widely used in high-tech electronic products such as computers, DVD players and game machines. At present, the main customers are LG Electronics, Asus Computer, Jianxing Electronics and other well-known IT manufacturers. Because the laser head and its series products condense the essence of high-tech such as optics, electronics, precision machinery, microcomputer, new materials and micro-processing, it is the most modern.

In addition, Keda Industry, the parent company of G Keda, promised in its 2005 annual report that the "Qingdao Low-temperature and Atmospheric LPG Storage and Transportation Project" will be injected into listed companies after completion, so that G Keda will hold the largest LPG base project in East China and create huge profit growth points. Because LPG is a seller's market, the price may soar and the company's development prospects will be first-class. G Kodak and Han's Laser are two giants of laser electronics in China, and they are forming two fist industries of laser and liquefied petroleum gas construction projects. Especially after the injection of liquefied petroleum gas project, the company's performance will increase substantially. At present, there are less than 50 million shares in circulation, and the share price is near the net asset value, far from the issue price of 8.6 yuan, which has good investment speculation value. Recently, the main force has been heavily involved in bargain hunting, and the market outlook is expected to disappear, which deserves close attention. Laser science is a new discipline developed in 1960s, and it is one of the major scientific and technological achievements after atomic energy, computer and semiconductor technology.

Laser speedology

Laser velocimetry is to measure the measured object twice at a specific time interval.

Obtain the moving distance of the measured object in this time period, so as to obtain the moving speed of the measured object.

Therefore, laser velocimetry has the following characteristics:

1. Because the laser beam is basically a ray, the estimated speed range is far from the effective range of radar speed measurement, and it can be measured beyond 1000M;

2, the speed measurement accuracy is high, and the error is

3. In view of the principle of laser velocimetry, the laser beam must be aimed at the reflection point perpendicular to the plane of the laser beam, and the success rate of laser velocimetry is low and difficult, especially for the police on duty, because the vehicle to be measured is too far away, in a moving state, or the plane of the car body is not large.

4. In view of the principle of laser velocimeter, laser velocimeter can not be used for transportation, but can only be used in a static state; Therefore, the laser velocimeter cannot be called "mobile electronic police". When used in a static state, the driver can easily find that there is detection, so the expected purpose can not be achieved.

5. It is expensive. At present, the price of laser velocimeter imported from regular channels (excluding framing and control parts) is at least about 1 10,000 USD.