This article introduces visible light lasers, the types of visible light lasers, and how a visible laser system based on nonlinear frequency conversion enables visible light generation.

Visible Laser is the laser that emit visible light.

Visible light lasers refer to lasers that emit visible light, and also include those laser devices that utilize nonlinear frequency conversion to obtain visible light.

Lasers that directly emit visible light The lasers that emit visible light directly account for only a small part of all lasers, and most of the lasers emitted by lasers are located in the infrared spectral region.

1. Some laser diodes emit visible light. Such as: GaInP and AlGaInP red laser diodes, GaN blue laser diodes.
2. The first laser is a ruby laser that emits a red laser at 694.3 nm.
3. The laser light emitted by the Ti:sapphire laser is mainly in the infrared spectral region, but can be adjusted down to about 650nm.
4. The GaN laser diode emits light at 400-480 nm.
5. There are some solid-state and fiber-optic upconversion lasers that also emit visible light.

1. HeNe lasers can emit visible light of various wavelengths, including common red light at 632.8nm, green light at 543.5nm, yellow light at 594.1nm, orange light at 604.6nm or 611.9nm.
2. Helium-cadmium lasers (see gas lasers) can emit blue light at 441.6 nm.
3. The argon ion laser mainly emits light at 514.5nm and 488nm, but can also emit visible light at 465.8nm, 472.7nm and 528.7nm.
4. Krypton ion lasers can also emit a variety of lasers in the visible region, the most common ones are 647.1nm and 530.9nm.
5. Copper vapor lasers (see gas lasers) can emit visible light at 510.6nm or 578.2nm.

Some dye lasers also have broad emission ranges throughout the visible spectral region.

1. The most common nonlinear frequency conversion method for green and blue visible light is to use nonlinear crystals to achieve frequency doubling inside or outside the cavity. This can be done using conventional solid-state lasers or vertical-cavity surface-emitting semiconductor lasers (VECSELs). The most common laser for this method utilizes the green visible light produced by frequency doubling of a 1064 nm neodymium laser.
2. The sum-frequency effect achieved by nonlinear crystals can also generate visible light. For example, a 1064nm Nd:YAG laser and a 1.5um fiber laser can generate red light at a sum frequency.
3. Raman lasers realized by pumping with ordinary lasers. Usually, a solid-state Q-switched laser or a continuous light laser is used, and an intra-cavity frequency doubling is used to realize a visible light Raman laser.
4. A broadband visible light source realized by supercontinuum generation.