IR Illuminator Wavelength Guide
The best choice of wavelength for an IR Illuminator depends on the device and its usage.
- Gen 1 Analogue tube device: up to 760–780nm
- Gen 2 Analogue tube device: up to 850nm
- Gen 2 High End: up to 900nm
- Gen 3 High End: up to 1000nm
- Digital Night Vision: up to 950–980nm
Generally, two wavelengths are available as additional illuminators to give enhanced range above onboard IR. Variants such as 875nm or 915nm are also available.
- 850nm: provides greater range for digital Night Vision. The wavelength is invisible to the eye, though a slight red glow can be observed if viewed directly.
- 940nm: completely invisible to the eye; no discernible red glow from the emitter, but range is decreased by up to 40–50%.
Depending on illuminator lens size, wattage, and quality, the distance viewed can be up to 400 metres for larger units, while smaller units are typically 200–250 metres. The ability of the unit to focus efficiently will affect the usable range.
There are two types of IR emitters: LED and Laser (VCSEL). The laser provides greater range, whereas LED often gives a cleaner image.
With the higher sensitivity of current Night Vision Units, there can be a tendency for the image to be washed out at shorter ranges.
Ultimately, performance is also affected by the price and quality of the unit, ranging from below £50 to commercial units costing £500–£600 or more.