Detailed explanation of several major characteristics of laser technology application

The world’s first laser was born in 1960, and my country developed the first laser in 1961. For more than 50 years, laser technology and applications have developed rapidly and have been combined with multiple disciplines to form multiple application technology fields, such as optoelectronic technology. , Laser medicine and photonic biology, laser processing technology, laser detection and measurement technology, laser holography technology, laser spectrum analysis technology, nonlinear optics, ultrafast lasers, laser chemistry, quantum optics, laser radar, laser guidance, laser separation Isotopes, laser controllable nuclear fusion, laser weapons, etc. The emergence of these intersecting technologies and new disciplines has greatly promoted the development of traditional industries and emerging industries.

　　 1. Introduction to the application of laser technology

Laser processing technology is a technology that uses the characteristics of the interaction between the laser beam and the substance to cut, weld, surface treatment, perforate, micro-process materials (including metals and non-metals), and as a light source to identify objects. Traditional applications The largest area is laser processing technology. Laser technology is a comprehensive technology involving multiple disciplines such as light, mechanics, electricity, materials and testing. Traditionally, its research scope can generally be divided into:

　　 1. Laser processing system. Including lasers, light guide systems, processing machine tools, control systems and inspection systems.

　　 2. Laser processing technology. Including laser cutting, laser welding, laser surface treatment, laser drilling, laser marking, laser scribing, laser trimming and other processing techniques.

　　Laser welding: sealing devices such as thick and thin automobile body plates, automobile parts, lithium batteries, cardiac pacemakers, sealed relays, and various devices that do not allow welding pollution and deformation. The lasers currently in use include YAG lasers, CO2 lasers and semiconductor pump lasers.

Laser cutting: automotive industry, computer, electrical casing, wooden knife mold industry, cutting of various metal parts and special materials, circular saw blades, acrylic, spring gaskets, copper plates for electronic parts below 2mm, and some metals Mesh panels, steel pipes, tin-plated iron plates, lead-plated steel plates, phosphor bronze, bakelite, thin aluminum alloys, quartz glass, silicon rubber, alumina ceramic sheets below 1mm, titanium alloys used in the aerospace industry, etc. The lasers used are YAG lasers and CO2 lasers.

　　Laser marking: It is widely used in various materials and almost all industries. The lasers currently in use include YAG lasers, CO2 lasers and semiconductor pump lasers.

　　 Laser drilling: Laser drilling is mainly used in aerospace, automobile manufacturing, electronic instrumentation, chemical and other industries. The rapid development of laser drilling is mainly reflected in that the average output power of the YAG laser used for drilling has increased from 400w five years ago to 800w to 1000w. The relatively 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 for watches and instruments, aircraft blades, and multilayer printed circuit boards. The lasers currently in use are mostly YAG lasers and CO2 lasers, as well as some excimer lasers, isotope lasers and semiconductor pump lasers.

　　Laser heat treatment: It is widely used in the automotive industry, such as the heat treatment of cylinder liners, crankshafts, piston rings, commutators, gears and other parts. It is also widely used in aerospace, machine tool industry and other machinery industries. The application of laser heat treatment in my country is much wider than that in foreign countries. The lasers currently in use are mostly YAG lasers and CO2 lasers.

　　Laser rapid prototyping: It is formed by combining laser processing technology with computer numerical control technology and flexible manufacturing technology. It is mostly used in mold and model industries. The lasers currently in use are mostly YAG lasers and CO2 lasers.

　　Laser coating: It is widely used in aerospace, mold and electromechanical industries. The lasers currently in use are mostly high-power YAG lasers and CO2 lasers.

　　 2. Laser processing technology and the focus of industrial development research and development

　　 The current focus of laser processing technology and industrial development research and development can be summarized as follows:

　　 (1) The research on a new generation of industrial lasers is currently in a technological update period, which is marked by the development and application of diode-pumped all-solid-state lasers.

　　(2) Research on the application of laser micromachining.

　　(3) Research on models of high-power CO2 and solid-state lasers and excimer lasers for laser processing, develop and develop special matching laser processing machine tools, and improve the cycle of stable operation of laser products on the production line.

　　(4) Intelligent processing system. System integration is not only processing itself, but also real-time detection and feedback processing. With the establishment of expert systems, processing system intelligence has become an inevitable development trend.

　　(5) Establish the detection method of laser processing equipment parameters and conduct method research.

　　(6) Research on laser cutting technology. Carry out the secondary development and industrialization of the existing laser cutting system to provide a 2-3 axis CNC CO2 cutting machine with good performance and low price

　　(7) Research on laser welding technology. Carry out laser welding process and materials, welding process requirements for equipment and welding process parameter monitoring and control technology research, so as to master the welding process of ordinary steel, non-ferrous metals and special steel.

　　(8) Research on laser surface treatment technology. Carry out CAD/CAM technology, laser surface treatment process, material performance and laser surface treatment process parameter monitoring and control research, so that the laser surface treatment process can be applied to production on a large scale.

　　(9) Research on laser processing beam quality and processing peripheral devices. Study the quality requirements of various laser processing technologies for laser beams, laser beam and processing quality monitoring technology, optical system and processing head design and development.

　　(10) Carry out research on laser processing technology, focusing on the research and application of material surface modification and heat treatment; carry out research on the application of laser rapid prototyping technology, and broaden the field of laser applications.

　　 3. Laser technology is the foundation of optoelectronic technology and industry, which will replace and promote the traditional electronic information industry

　　 The knowledge economy is dominant in the 21st century, and vigorously developing high and new technology is an inevitable choice to welcome the arrival of the era of knowledge economy. At present, the most important high and new technology recognized by the global industry as the fastest growing and increasingly widely used is optoelectronic technology, which is bound to become a pillar industry in the 21st century. In optoelectronic technology, one of its basic technologies is laser technology. The scientific community predicts that by 2005, the output value of the optoelectronic industry will reach the level of the output value of the electronics industry. By 2010, the information industry led by optoelectronic information technology will form an industry scale of 5 trillion US dollars. The industry may replace the traditional electronics industry. Optoelectronics technology will once again promote the revolution and progress of human science and technology after microelectronics technology.

The development of laser technology and industry in the 21st century will support and promote high-speed, broadband, mass optical communications and network communications, and will trigger a revolution in lighting technology. Small, reliable, long-life, and energy-saving semiconductors (LED) will dominate the market. In addition, a wide variety of optoelectronic consumer products will be launched (such as VCD, DVD, digital cameras, new color TVs, handheld computer electronics, smart phones, handheld audio playback equipment, photography, projection and imaging, office automation optoelectronic equipment such as laser printing, Fax and copying, etc.) and new information display technology products (such as CRT, LCD and PDP, FED, OEL flat panel displays, etc.) and enter people’s daily lives. Laser products have become the "eyes" and "nerves" of modern weapons, and optoelectronic military equipment will change the pattern of war in the 21st century.

In the process of promoting the rapid development of the optoelectronic industry in the future, the combination of laser technology and other technical application fields has the following aspects:

　　 1. Laser chemistry: The traditional chemical process generally involves mixing the reactants together, and then often requires heating (or pressure). The disadvantage of heating is that the molecules produce irregular motions due to increased energy. This motion destroys the original chemical bonds and combines them into new bonds. The bonds destroyed or generated by these irregular motions will hinder the expected chemical reactions.

　　 But if lasers are used to direct chemical reactions, not only can the above irregular movements be overcome, but also greater benefits can be obtained. This is because the laser carries highly concentrated and uniform energy, which can be precisely hit on the molecular bonds. For example, using ultraviolet lasers of different wavelengths to hit hydrogen sulfide and other molecules to change the phase difference between the two laser beams, it can be controlled. The breaking process of the molecule. The method of changing the laser pulse waveform can also be used to accurately and effectively hit the energy on the molecule to trigger a certain expected response.

　　The application of laser chemistry is very extensive. The pharmaceutical industry is the first area to benefit. The application of laser chemistry technology can not only accelerate the synthesis of drugs, but also eliminate unwanted by-products, making certain drugs safer and more reliable, and the price can be reduced. For another example, the use of lasers to control semiconductors can improve new optical switches, thereby improving computers and communication systems. Although laser chemistry is still in its infancy, its prospects are very bright.

　　2. Laser medical treatment: The application of lasers in medicine is divided into two categories: laser diagnosis and laser treatment. The former uses laser as an information carrier and the latter uses laser as an energy carrier. Over the years, laser technology has become an effective means of clinical treatment and a key technology for the development of medical diagnosis. It solves many problems in medicine and makes a contribution to the development of medicine. At present, it maintains a sustained and strong momentum of development in many aspects such as basic research, new technology development, and new equipment development and production.

The current excellent application research of laser medicine is mainly manifested in the following aspects: photodynamic therapy for cancer; laser therapy for cardiovascular diseases; excimer laser keratoplasty; laser therapy for benign prostatic hyperplasia; laser cosmetology; laser fiber endoscopic surgery; laser Laparoscopic surgery; laser thoracoscopic surgery; laser arthroscopic surgery; laser lithotripsy; laser surgery; laser application in anastomosis; laser application in oral, maxillofacial surgery and dentistry; low-level laser therapy, etc.

　　The recent research highlights of laser medicine include:

(1) Study the relationship between laser and biological tissues, especially the relationship between laser and biological tissues that have been important applications in many effective therapies; study different laser parameters (including wavelength, power density, energy density and operation mode) Etc.) Obtain systematic data on the relationship between different biological tissues, human organs and diseased tissues;

(2) To study the cellular biological effects of low-level lasers and their mechanism of action, including; the relationship between low-level lasers and cell biological phenomena (gene regulation and apoptosis), molecular biological mechanisms of low-level laser analgesia, and low-level lasers and cells The relationship and mechanism of immunity (antibacterial, antitoxin, antiviral, etc.);

　　(3) In-depth research on the mechanism of photodynamic therapy, laser interventional therapy, laser cardiovascular angioplasty and myocardial vascular reconstruction, and actively explore other new laser medical technologies.

(4) Conduct developmental research on important and novel photonic devices and instrument settings in medical photonics technology, such as the development of medical semiconductor laser systems, excimer laser equipment for keratoplasty and angioplasty, laser cosmetology (replacement and wrinkle removal, Hair transplant) equipment or other new laser equipment, the development of medical laser systems with new working bands, and the development of Ho: YAG and Er: YAG laser scalpels.

3. Ultra-fast and ultra-strong laser: Ultra-fast and ultra-strong laser is mainly based on the research and application of femtosecond laser. As a unique scientific research tool and method, the main application of femtosecond laser can be summarized in three aspects. That is, the application of femtosecond laser in the ultrafast field, the application in the super field, and the application in ultrafine processing.

　　 Femtosecond lasers play a role in rapid process diagnosis in the field of ultrafast phenomena research. Femtosecond laser is like a very fine clock and a super high-speed "camera" that can analyze and record some rapid processes in nature, especially at the atomic and molecular level.

The application of 　　 femtosecond laser in the super-intensity field (also known as strong field physics) is due to the fact that the peak power and light intensity of a femtosecond pulse with a certain energy can be very high. The electromagnetic field corresponding to such a strong light will be much larger than the Coulomb field in the atom, so that all the electrons in the atom are easily stripped out. Therefore, the femtosecond laser is an important tool for studying high-order nonlinear and multiphoton processes in atomic and molecular systems. The energy density corresponding to the femtosecond laser can only exist in a nuclear explosion. Femtosecond intense light can be used to generate coherent X-rays and other extremely short-wavelength light, which can be used for controlled nuclear fusion research.

　　The use of femtosecond lasers for ultra-fine processing is another important application research field of femtosecond laser technology besides the use of femtosecond lasers for ultrafast phenomenon research and super-strong phenomenon research. This application has only been developed in recent years, and there have been many important developments. Different from femtosecond superfast and femtosecond super research, femtosecond laser ultrafine processing is closely related to advanced manufacturing technology, which can play a more direct role in promoting the development of certain key industrial production technologies. Femtosecond laser ultra-fine processing is an extremely eye-catching frontier research direction in the laser and optoelectronic industries in the world today.

　　4. Research on new lasers: Laser rangefinders are the starting point for laser applications in the military. The application of them to artillery systems greatly improves the accuracy of artillery shooting. Compared with radio radar, lidar has a small divergence angle and good directivity, so its measurement accuracy is greatly improved. For the same reason, there is no "blind zone" in lidar, so it is especially suitable for tracking and measuring the initial stage of missiles. However, due to the influence of the atmosphere, lidar is not suitable for searching in a large range, and can only be used as a powerful complement to radio radar. There are also precise laser-guided missiles, as well as the use of laser weapon technology used on the simulated battlefield. On the battlefield of the actual laser combat exercise, it resembled the actual war scene.

　　The advantages of laser weapons; no need to perform ballistic calculations; no recoil; simple operation, flexible maneuverability, wide range of use; no radioactive pollution, high cost-effectiveness.

　　The classification of laser weapons: lasers with different power densities, different output waveforms, and different wavelengths will produce different killing and destructive effects when interacting with different target materials. There are many types of lasers with different names. According to the working medium, there are solid-state lasers, liquid lasers, and molecular, ion, and excimer gas lasers.