Now you see it, now you don’t.
Many earlier cloaking systems turned objects invisible only under wavelengths of light that the human eye can’t see. Others could conceal only microscopic objects. But a new system, developed at Massachusetts Institute of Technology and the Singapore-MIT Alliance for Research and Technology Centre, works in visible light and can hide objects big enough to see with the naked eye.
The cloak is made from two pieces of calcite crystal stuck together in a certain configuration.
Calcite is highly anisotropic, which means that light coming from one side will exit at a different angle than light entering from another side. By using two different pieces of calcite, the researchers were able to bend light around a solid object placed between the crystals. Whatever is put under this gap, it looks from the outside like it is not there.
VIA The Presurfer