Infrared illuminators work by emitting light in the infrared spectrum, or by reflecting ambient light. The human eye cannot detect IR light; however, NVDS give people the ability to detect the light emitted or reflected by the IR illuminator. Infrared lights are used as additional light sources, and are especially useful in environments where the level of natural light is extremely low, or for locating and marking targets.
NVD infrared lights are divided into three major groups:
- IR LED: The most popular type of IR lights for night vision. These devices produce IR light that can be detected only by other night vision units. These are the safest type of IR lights.
- Lasers: Units that work on the amplification of light, stimulated by generated photons. These lasers can emit radiation, and can be dangerous when handled poorly or subjected to unsafe conditions.
- Filtered lamps: Units that consist of an incandescent lamp and an infrared filter. Such filters block all parts of the spectrum, except for infrared.