Infrared light
Infrared (IR) light is a type of electromagnetic radiation that lies between the visible end of the light spectrum, and the microwave spectrum (Vollmer and Mollmann, 2010). Its wavelength ranges from about 800 nm to 1 mm and it is emitted particularly by heated objects.
An Er: YAG laser (erbium-doped yttrium aluminium garnet laser, erbium YAG laser) is a solid-state laser whose active laser medium is erbium-doped yttrium aluminium garnet (Er:Y3Al5O12). Er: YAG lasers typically emit light with a wavelength of 2940 nm, which is infrared light.