Principle and development prospect of UV DPSS laser system

The importance of laser is self-evident, it can be widely used in industry, medicine, communication, military and other fields, and promote the process of social development. Therefore, some people call it another important invention of human beings since the 20th century after the continuation of nuclear energy, computers and semiconductors. At the same time, it is also known as "the fastest knife", "the fastest ruler" and "the brightest light".

Light is when electrons in atoms absorb energy, transition from low energy level to high energy, and then fall back from high energy to low energy, and are released in the form of energy photons released when they fall back. The laser is the photon array that is induced (excited), and the photons in this photon array have the same optical characteristics and the same pace.

UV laser

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At present, according to the working medium, lasers can be divided into four categories: gas lasers, solid-state lasers, semiconductor lasers and dye lasers. Free electron lasers have also been developed. High-power lasers are usually pulsed output.

The first ruby ​​laser came out in 1960, and my country developed the first laser in 1961, opening a new chapter in the field of lasers. Lasers have the characteristics of good directionality, high brightness, good monochromaticity and good coherence. After more than 50 years, laser technology and applications have developed rapidly. Among them, all-solid-state UV lasers are small in size, long in life, compact in structure and easy to maintain. A series of advantages have become one of the research fields for the development of laser technology.

Ultraviolet laser wavelength is 355nm, small spot, narrow pulse width, multiple wavelengths, fast speed, good penetration, less heat, large output energy, high peak power and good material absorption, etc. It belongs to cold light source, also known as "" "Cold working" can be absorbed by the material better, and the damage to the material is also small. Compared with conventional CO2 lasers and fiber lasers, it can meet the requirements of most industrial precision machining. At present, solid-state UV lasers are widely used in various industries based on their various performance advantages, and have become one of the current mainstream industrial-grade lasers.

Principle of solid-state ultraviolet laser light output

The laser must have the above three parts, the pump source, the working substance and the optical resonator, and the laser using solid laser material as the working substance. Under the action of the pump source, the working substance undergoes a population inversion distribution and becomes an activated substance, which has the effect of light amplification. A part of the amplified light is fed back to participate in the excitation, and the resonator oscillates. After certain conditions are met, laser light can be generated.

1. Pump source: its function is to give energy to the working substance and excite the atoms from the low energy level to the external energy of the high energy level. Usually there can be light energy, thermal energy, electrical energy, chemical energy and so on.

2. Working material: The core of the laser, only the material that can achieve energy level transition can be used as the working material of the laser.

3. Optical resonator: make the stimulated radiation of the working substance continue; continuously accelerate the photons; limit the direction of the laser output.

Laser marking principle

Laser marking is a marking method that uses a high-energy-density laser to locally irradiate the workpiece to vaporize or change the color of the surface material, thereby leaving a permanent mark. Laser marking can print various characters, symbols and patterns, etc., and the character size can range from millimeters to micrometers, which is of special significance to the anti-counterfeiting of products.

The focused very fine laser beam is like a tool, which can remove the material on the surface of the object point by point. Its advanced nature is that the marking process is non-contact processing without mechanical extrusion or mechanical stress, so it will not damage the processed items; The laser focused size is small, the heat-affected area is small, and the processing is fine. Therefore, some processes that cannot be achieved by conventional methods can be completed.

Application and Development

Driven by the 3C application market, my country's ultraviolet laser market has developed rapidly in the past two years. After 2017, the market showed a linear growth trend. In 2018, the market demand for ultraviolet lasers declined slightly. Affected by the epidemic, many processing industries developed slowly, and began to grow slowly in 2019. Although it is not as popular as 2017, it is relatively Compared with 2018, it shows a slight growth trend, which reflects the application and development trend of domestic ultraviolet lasers today.

technology fortress

As the mainstream direction of industrial processing, ultraviolet lasers have been developed like fiber lasers in recent years, and the power has been continuously increased, extending from the earliest 3W, 5W, to 10W, 15W, and then to 30W, 40W.

In view of the continuous improvement of laser processing efficiency and requirements for industrial applications, nanosecond ultraviolet lasers with more than 5 W have become the new favorite in the market. Therefore, medium and high power nanosecond ultraviolet lasers with high power, narrow pulse width and high repetition frequency can meet the needs of different customers. Processing application requirements for UV laser output power.

In order to adapt to the improvement of industrial processing accuracy requirements, RFH Laser independently developed and produced solid-state ultraviolet lasers. According to the domestic use environment, this series of products adopts two forms of full air cooling and water cooling, with stable product performance, small size, compact structure and low power consumption. . The output laser beam is the fundamental mode, with good beam quality and high peak power, which can meet the requirements of most industrial precision machining.