Infrared filters or IR filters are optical filters that allow infrared light to pass through. In addition, there are the IR cut filters or IR cut filters that block infrared light. Both types of filters are used in photography in digital cameras, infrared photography, light barriers, remote controls, infrared transmission links and optical transmission technology.
Infrared filters are bandpass filters that transmit infrared light in the wavelength range from 800 nm. Such filters are used as optical filters in optical networks and in infrared photography and filter out the frequency ranges above 300 GHz that are relevant for the applications.
In contrast, IR cutoff filters are used as protective filters to prevent color distortion and damage to image sensors. In combination with a UV blocking filter, an IR blocking filter can form a daylight filter that only transmits wavelengths of daylight between 380 nm and 780 nm.