What is SWIR (Short Wave Infrared)?

Glossary Definition

SWIR (Short Wave Infrared) is a portion of the electromagnetic spectrum with wavelengths from 0.9 to 1.7 microns. The short-wave infrared (SWIR) portion of the spectrum offers unique capabilities, often complementary to LWIR and MWIR imaging. Imaging in SWIR uses reflected light, much like the slightly shorter wavelengths of the visible spectrum.

The main advantages of using SWIR imaging in military applications is that SWIR cameras often “see through” and generate higher contrast images in adverse environments and challenging weather conditions, especially compared to visible images. Conditions such as fog, haze, rain and dust are all penetrated by SWIR imaging due to the reduced Rayleigh scattering of the longer wavelengths it utilizes when compared to visible imaging.

Many SWIR systems are marketed as low light or as good camera systems for complete darkness. This isn’t always the case (particularly with long range). Unlike MWIR and LWIR, SWIR imaging does not depend on the intrinsic black body emissivity of target objects, therefore it is usually not referred to as a form of thermal imaging. This means that SWIR requires illumination in long range scenarios. Infiniti is currently developing an effective long-range SWIR illuminator for such applications.