Invisible beams

The infrared is a kind of light which appears over red in a spectrum resulting from the use of a prism. The 'infra' part comes from the fact that energy of this kind of light (converted into one quantum, that is 'a parcel') is smaller than the energy of the visible light.

The infrared radiation is not visible, but can be felt, e.g. it is hot near a bonfire. The night-vision device used by the army is a screen sensitive to infrared radiation. But can you see it with a naked eye?

Have a look at those photos of a TV remote controller. The photo was taken during 'transmission' with a regular digital camera. The video cameras operate similarly - their sensors see the infrared.