Spectroscopic polarimeter

A spectroscopic polarimeter and methods of manufacturing the same are provided. The spectroscopic polarimeter is described as being fabricated by etching or patterning grooves into a substrate with a centrally smooth area, laying down an opaque thin layer of metal, etching out a central cavity from the metal, laying down a thin layer of dielectric material, and then laying down metal over the cavity. Optionally, before or after the dielectric layer is laid, a thicker metal barrier at the edge of the design can be laid as well.