Infrared radiation is one type of electromagnetic wave. Any object at room temperature and molecules of matter can emit infrared radiation. It is undetectable by human eyes.
The wavelength of infrared radiation is slightly longer than visible light. The range of infrared radiation is from m to m.
Detection of infrared radiation,
Infrared radiations are detected by a device named photometers.
A photometer is an excellent device that detects radiations from the range infrared to ultraviolet.
So, infrared radiation can be detected using photometers.