Infrared is light that is between the visible and microwave portions of the electromagnetic spectrum. It is some times used in optical communications to transmit a digital signal between devices over a short distance.
Infrared is also used in night vision applications where it converts ambient light photons into electrons which are amplified and converted back to visible light.
Infrared is also used in night vision applications where it converts ambient light photons into electrons which are amplified and converted back to visible light.