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What is SWIR?
First, the word SWIR (pronounced ‘sweer’) is an acronym meaning Short Wavelength InfraRed, also frequently referred to as shortwave infrared. SWIR generally refers to the wavelength band of light between 900nm and 2500nm.
Since standard silicon sensors have an upper limit of approximately 1000nm, SWIR imaging requires sensors and camera components capable of operation in the shortwave infrared range, which exceeds the upper limit of silicon. Indium gallium arsenide (InGaAs) sensors are commonly used in SWIR imaging, typically covering the 900nm to 1700nm range. But InGaAs devices are inherently expensive and face challenges in scaling to smaller pixel pitches and higher resolution arrays.
Unlike Long Wave Infrared (LWIR) light, which is emitted from the object itself, SWIR or shortwave infrared light is similar to visible light in that photons are reflected or absorbed by an object, providing the strong contrast needed for high-resolution imaging. While LWIR imagers give off more poorly defined thermal images, SWIR imagers deliver high-resolution images, much like visible light cameras.
SWIR imagers are used in a large number of applications including silicon inspection, laser beam profiling, hyperspectral imaging, chemical and plastics sensing, machine vision imaging, agricultural sensing, surveillance systems, and medical imaging. They are also intended for use in mobile phone facial recognition sensors, and autonomous vehicle imaging though obscured environments.