Laser marking machine mainly uses optical fiber marking machine as a laser device. It is usually used for metal carving and plastic carving. The core of this paper is the laser which uses rare earth doped glass fiber as gain medium and can be used in fiber amplifier.
On the basis of development: under the action of pump light, it is easy to form high power density in optical fiber, which makes the laser energy level of laser working substance "reverse the particle number". When the positive feedback loop (to form the resonator) is added properly, the laser oscillation output is formed, which is a glass solid fiber drawn from SiO2 as the matrix material. Its photoconductivity principle is based on the total reflection principle of light, That is, when the refractive index of light is greater than the critical angle, when the medium with large optical density is incident on the medium with small refractive index, total reflection occurs, and all the incident light is reflected on the medium with large refractive index, and no light passes through the medium with small refractive index to remove the medium.
The common bare fiber is usually composed of a high refractive index glass core in the center, a low refractive index silica glass cladding in the middle and a reinforced resin coating in the outermost layer. According to the propagation mode of light wave, it can be divided into single-mode fiber and multimode fiber. Single mode fiber has a small core diameter, and can only spread one optical mode with a small dispersion between modes.
It has a relatively large core diameter and can transmit various modes of light, but the dispersion between modes is very large. According to the refractive index distribution, it can be divided into step index (SI) fiber and gradient index (GI) fiber. Taking the rare earth doped laser marking machine as an example, the fiber core doped with rare earth ions is used as the gain medium. The doped fiber is fixed between two mirrors to form a resonant cavity, and the pump light enters the fiber from M1
Laser marking machine output from m2. When the pump light passes through the optical fiber, the rare earth ions in the optical fiber absorb the pump light, and the electrons are excited to a higher excitation level to realize the ion number inversion. The inverted particles are transferred from the high energy level to the ground state by radiation formation, and the laser is output.