定义：
发射可见光的激光器。

可见光激光器指的是发射可见光的激光器，同时也包括那些利用非线性频率变换得到可见光的激光装置。 
直接发射可见光的激光器 直接发射可见光的激光器只占全部激光器的较少的一部分，大部分的激光器发射的激光位于红外光谱区域。 
以下的一些固体激光器可以发射可见光： 

1. 一些激光二极管可以发出可见光。如：GaInP以及AlGaInP的红色激光二极管，GaN的蓝色激光二极管。 
2. 第一台激光器即是发射694.3nm的红色激光的红宝石激光器。 
3. 钛蓝宝石激光器发射的激光主要在红外光谱区域，但可以调节降低到约650nm。 
4. 氮化镓激光二极管发射光在400-480纳米。 
5. 有一些固体和光纤的上转换激光器也可以发射可见光。 

也有一些气体激光器可以发射可见光： 

1. 氦氖激光器可以发散多种波长的可见光，包括常见的的632.8nm的红光，还有543.5nm的绿光、594.1nm的黄光、604.6nm或611.9nm的橙光。 
2. 氦镉激光器（参阅气体激光器）可以发射441.6nm的蓝光。 
3. 氩离子激光器主要发射光在514.5nm和488nm，但也可发射465.8nm，472.7nm和528.7nm的可见光。 
4. 氪离子激光器也可以在可见光区域发射多种激光，常见的主要在647.1nm和530.9nm。 
5. 铜蒸气激光（参阅气体激光器）可以发射510.6nm或578.2nm的可见光。 

一些染料激光器也在整个可见光谱区具有较宽的发射范围。 

基于非线性频率变换的可见激光系统 有多种方法都可以通过非线性频率变换实现可见光的产生： 

1. 对于绿色和蓝色可见光的最常用的非线性频率变换方法是在腔内或者腔外利用非线性晶体实现倍频。这可以利用传统的固体激光器，也可以利用垂直腔面发射半导体激光器（VECSELs）。这种方法最常见的激光器是利用1064nm的钕激光器倍频产生的绿色可见光。 
2. 利用非线性晶体实现的和频效应也可以产生可见光。例如，利用1064nm的Nd：YAG激光器和一个1.5um的光纤激光器可以和频产生红光。 
3. 利用普通激光器泵浦实现的拉曼激光器。通常使用固体的调Q激光器或者连续光激光器，并利用腔内倍频实现可见光的拉曼激光器。 
4. 利用超连续谱产生实现的宽带可见光光源。

Definition: lasers (or other laser-based light sources) emitting visible light

More general terms: lasers

More specific terms: red lasers, yellow and orange lasers, green lasers, blue lasers

The term visible lasers is used to denote lasers emitting visible light, or sometimes laser devices generating visible light via nonlinear frequency conversion. Visible light (for human eyes) corresponds to optical wavelengths roughly between 400 nm and 700 nm.

Lasers with Direct Visible Emission

Laser which directly emit visible light constitute a minority – most lasers emit in the infrared spectral region. Some examples of solid-state lasers emitting visible light are:

• Various laser diodes can emit visible light. Examples are GaInP and AlGaInP-based red laser diodes, and GaN-based blue-emitting diodes.
• The first demonstrated laser was a ruby laser emitting at 694.3 nm.
• Titanium–sapphire lasers emit mostly in the infrared spectral region, but can be tuned down to roughly 650 nm.
• There are various upconversion lasers, including both bulk and fiber lasers, with visible light emission.

There are also various gas lasers emitting visible light:

• The helium–neon laser was the first gas laser with visible emission. It can emit on various visible wavelengths, including the well-known 632.8 nm red wavelength but also in the green (543.5 nm), yellow (594.1 nm) and orange (604.6, 611.9 nm) spectral region.
• Helium–cadmium lasers (→ metal vapor lasers) emit in the blue at 441.6 nm.
• Argon ion lasers emit mostly at 514.5 and 488 nm, but also at 465.8, 472.7 and 528.7 nm.
• Krypton ion lasers emit at various wavelengths throughout the visible spectrum, in particular at 647.1 nm and 530.9 nm.
• Copper vapor lasers (→ metal vapor lasers) emit at 510.6 nm (green) or 578.2 nm (yellow).

Finally, various dye lasers have broad emission ranges throughout the visible spectral region.

See also the articles on red, green and blue lasers.

Visible Laser Systems Based on Nonlinear Frequency Conversion

Various methods allow the generation of visible light in laser diodes via nonlinear frequency conversion:

• The most frequently used approach particularly for green and blue emission is frequency doubling, either intracavity or in an external nonlinear crystal (single-pass or resonant). This can be applied to traditional solid-state bulk lasers and also to VECSELs. Most common are green-emitting laser sources based on frequency-doubled 1064-nm neodymium lasers.
• Sum frequency generation in a nonlinear crystal can generate visible light. For example, sum frequency mixing of a 1064-nm Nd:YAG laser and a 1.5-μm fiber laser leads to red light.
• A Raman laser can be pumped with light from a regular laser. This is most often done with solid-state bulk lasers, which may be Q-switched or continuous-wave, and often intracavity frequency doubled.
• For broadband visible radiation, there are laser sources involving supercontinuum generation.