Infrared light is a type of electromagnetic radiation that has longer wavelengths than visible light, typically ranging from about 700 nanometers to 1 millimeter. It is not visible to the human eye but can be felt as heat. Infrared light is commonly used in various applications, including remote controls, thermal imaging, and night vision technology. This form of light is divided into three categories: near-infrared, mid-infrared, and far-infrared. Near-infrared is often used in fiber optic communications, while thermal imaging devices utilize mid-infrared and far-infrared to detect heat emitted by objects.