This chart shows colors of the visible light spectrum, and the associated wavelengths in nanometers. Ranges are traditionally given as: ultraviolet light, 100-400 nm; visible light, 400-750 nm; and infrared, 750 nm-1 mm.
The infrared laser pointer has a wavelength out of the red light ,and is invisible for human eyes. Check here invisible lasers:
Armlaser has 400MW 808NM INFRARED LASER POINTER
It has a wavelength of 808nm and the laser beam is invisible, you can only see the laser dot .
Different regions in the infrared
Objects generally emit infrared radiation across a spectrum of wavelengths, but only a specific region of the spectrum is of interest because sensors are usually designed only to collect radiation within a specific bandwidth. As a result, the infrared band is often subdivided into smaller sections.
The International Commission on Illumination (CIE) recommended the division of optical radiation into the following three bands:
IR-A: 700 nm–1400
IR-B: 1400 nm–3000 nm
IR-C: 3000 nm–1 mm
Near-infrared (NIR, IR-A DIN): 0.75-1.4 µm in wavelength, defined by the water absorption, and commonly used in fiber optic telecommunication because of low attenuation losses in the SiO2 glass (silica) medium. Image intensifiers are sensitive to this area of the spectrum. Examples include night vision devices such as night vision goggles.
Short-wavelength infrared (SWIR, IR-B DIN): 1.4-3 µm, water absorption increases significantly at 1,450 nm. The 1,530 to 1,560 nm range is the dominant spectral region for long-distance telecommunications.
Mid-wavelength infrared (MWIR, IR-C DIN) also called intermediate infrared (IIR): 3-8 µm. In guided missile technology the 3-5 µm portion of this band is the atmospheric window in which the homing heads of passive IR 'heat seeking' missiles are designed to work, homing on to the IR signature of the target aircraft, typically the jet engine exhaust plume.
Long-wavelength infrared (LWIR, IR-C DIN): 8–15 µm. This is the "thermal imaging" region, in which sensors can obtain a completely passive picture of the outside world based on thermal emissions only and requiring no external light or thermal source such as the sun, moon or infrared illuminator. Forward-looking infrared (FLIR) systems use this area of the spectrum. Sometimes also called the "far infrared."
Far infrared (FIR): 15-1,000 µm (see also far infrared laser).