Nonspecular reflector with diffusely reflecting superconductor and protection coating

Claim 1

A reflector comprising a body of a ceramic oxide superconductive material which is superconductive at a temperature below a critical temperature and which is semiconductive or insulating at a temperature above said critical temperature, said critical temperature being a temperature above which said body is not superconducting and below which said body is superconducting, said body having a surface of said ceramic oxide superconductive material treated to be diffusely reflective and adapted to be disposed in a path of electromagnetic radiation to be reflected and of a wavelength longer than an optical binding energy of paired charge carriers of the superconductive ceramic oxide material and a protective coating of diamond-like carbon or magnesium fluoride on said body in said path.