A black body is a hypothetical object in which all light approaching is perfectly absorbed and the object act as a perfect radiator often of infrared radiation. They can be used to model stars, black holes and humans in some cases. Since producing a real black body is impossible, something close can be achieved by letting the light enter an enclosed cavity as shown below:
In laser laboratories similar devices are used as end points for the beam as they won’t allow it to burn whatever would have been consequently in the laser’s way and also prevent the beam from scattering and causing a serious health risk. Looking into one of these laser sinks is quite unnerving. It is like looking into a well, so deep that you can’t see the bottom, but it is a cylinder only 10cm long. It’s not the same blackness as when you see a black car, let’s say, it is the blackness that comes from nothing, no light at all.Recently there has been talk of using an interferometer to try and produce another close approximate of a black body. An interferometer works by splitting a beam and then reuniting the two halves to produce interference. By manipulating with the magnetic permeating field and by repeated splits of a beam a design is being drawn up for a unidirectional perfect absorber and the opposite, a unidirectional perfect radiator using these idea to try and replicate the two key features of all black bodiesD.