Lasers are one of the essential core components in modern laser processing systems. With the development of laser processing technology, lasers are also constantly developing, and many new types of lasers have emerged. The lasers used in early laser processing were mainly high-power CO2 gas lasers and lamp-pumped solid-state YAG lasers. From the perspective of the development history of laser processing technology, the first laser that appeared was the sealed CO2 laser tube in the mid-1970s. Up to now, the fifth generation of CO2 laser—diffusion-cooled CO2 laser has appeared. It can be seen from the development that the early CO2 lasers tended to increase the laser power, but when the laser power reached a certain level, the beam quality of the laser was valued, and the development of the laser shifted to increase the beam quality. The diffusion-cooled slab-type CO2 laser that is close to the diffraction limit has better beam quality, and has been widely used since it has been launched, especially in the field of laser cutting, and is favored by many companies.
At the beginning of the 21st century, another new type of laser, the semiconductor laser, appeared. Compared with traditional high-power CO2 and YAG solid-state lasers, semiconductor lasers have obvious technical advantages, such as small size, light weight, high efficiency, low energy consumption, long life, and high metal-to-semiconductor laser absorption. With the continuous development of laser technology, other solid-state lasers based on semiconductor lasers, such as fiber lasers, semiconductor-pumped solid-state lasers, and sheet lasers, are also developing rapidly. Among them, fiber lasers are developing rapidly, especially rare earth-doped fiber lasers, which should be widely used in the fields of optical fiber communication, optical fiber sensing, and laser material processing.
Due to the various outstanding characteristics of lasers, they were quickly used in various fields such as industry, agriculture, precision measurement and detection, communication and information processing, medical treatment, military affairs, etc., and caused revolutionary breakthroughs in many fields. In addition to the military use of lasers in communications, night vision, early warning, and ranging, a variety of laser weapons and laser-guided weapons have also been put into practical use.
1. The laser is used as a heat source. The laser beam is small and has huge power. If it is focused by a lens, the energy can be concentrated on a small area and generate huge heat. For example, people use the concentrated and extremely high energy of the laser to process various materials, and can drill 200 holes on a needle; The means have achieved good results in the practical application of medical treatment and agriculture.
2. Laser ranging. As a light source for distance measurement, laser can measure a long distance with high precision due to its good directionality and high power.
3. Laser communication. In the field of communications, an optical cable that uses laser beams to transmit signals can carry the amount of information equivalent to 20,000 copper telephone wires.
4. The application of controlled nuclear fusion in the air. Shoot the laser into the mixture of deuterium and tritium, the laser brings them huge energy, generates high pressure and high temperature, promotes the fusion of the two nuclei into helium and neutrons, and releases huge radiation energy at the same time. Because the laser energy can be controlled, the process is called controlled fusion.
In the future, with the further research and development of laser technology, the performance of lasers will be further improved and the cost will be further reduced, but its application range will continue to expand and will play an increasingly important role.
Laser pointers are small low-power lasers that use lasers for indication purposes. They are general civilian products, also known as laser pointers, star pointers, etc. It is a product with a wide range of uses: teaching and scientific research units are used as instructions for teaching, academic reports, conferences and other occasions with video equipment; military units are used to cooperate with large-screen command system instructions; tourist units are used for tour guides; construction and decoration It is used by the supervisory unit for the instruction of construction and decoration acceptance, etc. In some occasions, it can also be fixed as an orientation tool; it can also be used as a gift.
When using a laser cutting machine, the laser output of the laser may cause the following accidents:
(1) If the laser beam touches combustibles, it will cause a fire. We all know that the power of the laser generator is very high, especially when encountering a high-power laser cutting machine, the temperature of the emitted laser is very high. When the laser emits and touches flammable objects, it is very likely to cause a fire.
(2) The machine may produce harmful gas during operation. For example, when cutting with oxygen, there is a chemical reaction with the cutting material to generate impurities such as unknown chemical substances or fine particles. After being absorbed by the human body, it may produce an allergic reaction or cause discomfort in the lungs and other respiratory tracts. Protective measures should be taken when performing operations.
(3) Directly irradiating the human body with laser light will be harmful to the human body. Laser damage to the human body mainly includes damage to the eyes and skin. Among the laser injuries, the damage to the eyes is the most serious to the body. And the eye damage is permanent. Therefore, you must pay attention to protect your eyes when performing operations.
Therefore, the cutting environment should strictly prohibit flammable objects from approaching the machine and keep ventilation, and the workplace should also be equipped with fire extinguishers. Staff must take self-protection measures when performing operations.
Fiber lasers can achieve laser output in the 800nm-2100nm band, and the maximum power has reached the order of 10,000 watts. The application has also expanded from optical communication to laser processing, laser marking, image display, bioengineering, medical and health and other fields. The development trend of fiber lasers in the future will be reflected in the following aspects:
(1) Improvement of the performance of the fiber laser itself: How to improve the output power and conversion efficiency, optimize the beam quality, shorten the length of the gain fiber, improve the system stability and make it more compact will be the focus of future research in the field of fiber lasers.
(2) Development of new fiber lasers: in the time domain, ultrashort pulse mode-locked fiber lasers with smaller duty cycles have always been a research hotspot in the laser field, and high-power femtosecond-level pulsed fiber lasers have been long-term pursuits. The breakthrough in research in this field can not only provide an ideal light source for optical communication time division multiplexing (OTDM), but also effectively promote the development of related industries such as laser processing, laser marking and laser encryption. In the frequency domain, broadband output and tunable fiber lasers will become a research hotspot. A nonlinear fiber laser using ZEBLAN materials (Zr, Ba, La, Al, Nd) as the laser medium has attracted people’s attention. It has quite wide bandwidth and low loss, and can realize several bands of wavelength up-conversion. It is praised by experts as the next-generation communication material. If it can be mass-produced, it will generate a market of billions of dollars in the fields of laser printing and large-screen display. . It can be predicted that with the improvement of related technologies, fiber lasers will develop into a wider field, and may become a new generation of light sources to replace solid-state lasers and semiconductor lasers, forming an emerging industry.