Laser is another major invention of humanity since the 20th century, following nuclear energy, computers, and semiconductors. It is known as the "fastest knife," "most accurate ruler," and "brightest light. English name Light Amplification by Stimulated Emission of Radiation, which means "amplification by stimulated radiation". The full English name of laser fully expresses the main process of manufacturing laser. The principle of laser was discovered by the famous Jewish physicist Einstein as early as 1916.

The light emitted by atoms is called "laser". Laser: When electrons in atoms absorb energy and transition from low to high energy levels, and then fall back from high to low energy levels, the released energy is released in the form of photons. A photon beam (laser) induced (excited), in which the optical properties of photons are highly consistent. Therefore, compared to ordinary light sources, lasers have better monochromaticity, directionality, and higher brightness.

Laser applications are very extensive, including laser marking, laser welding, laser cutting, fiber optic communication, laser ranging, laser radar, laser weapons, laser records, laser correction, laser beauty, laser scanning, laser mosquito killer, LIF non-destructive testing technology, and so on. Laser systems can be divided into continuous wave lasers and pulse lasers.