On this day in 1952 André Henri Mirau was granted the patent for INTERFEROMETER. U.S. Patent No. 2,612,074.
The present invention relates to interferometers and other measurement apparatus (for instance for studying superficial polish or the refractive index of transparent liquids or solids), based upon interference method measurement of differences of optical paths. This invention consists, chiefly, in separating light into two beams by means of a separator including a semi-reflecting layer, in combination with at least one mirror or other optical device capable of giving said beams, on their way to the viewing system, two substantially equal paths, producing the phenomenon of interference.
