The white "super-continuous" laser mentioned by many people really looks white, because the color of the laser becomes "white" because of the superimposition of visible light. In fact, color is only a reflection of the artificially prescribed light wavelength (or frequency). White laser is the laser after the visible light spectrum is broadened, and supercontinuum lasers can also be produced in other wavelength bands. However, with the development of laser technology, people began to develop another type of lasers, namely mode-locked lasers. The typical characteristics of this type of lasers are that they have a wide spectrum (currently up to a few hundred nm) and the pulse duration is very short (the shortest). For a few femtoseconds (10-15s)). The emergence of this type of laser laid the foundation for white-light lasers, especially after the emergence of Ti:Sapphire lasers in the 1980s. Helium-cadmium ion gas laser. Because of the special energy level structure of Gd ions, the light transition can emit the three primary colors of red, green and blue, and their proportions are appropriate to form white light. Of course, there is some color difference compared with natural white light.
Monochromaticity is one of the basic characteristics of lasers, so the laser itself cannot be white, because white itself contradicts monochromaticity. The white Laser pointer uses a monochromatic laser to convert it into white light. Its advantages of low power consumption, high brightness, small size, high efficiency and practicality can be widely used in national defense, military, mountain search, maritime and field search, forest fire prevention, fire protection, rescue, patrol, etc. and as a tactical gun light. It can also be used with the camera to take photos and collect evidence from a distance, and can be used for special police, traffic police, criminal police, public security, etc. Due to the use of lasers as energy sources, white lasers are born with the genes of lasers, that is, they have the characteristics of high brightness and high collimation.