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Thin-film optical filters for spatial frequencies

Thin-film optical filters selectively absorb, transmit and reflect certain parts of the electromagnetic spectrum. We propose and analyze a new concept of thin-film filter that directly and selectively transmits and reflects certain parts of the spectrum of spatial frequencies. The transmittance and reflectance are short-pass functions or long-pass functions of the angle of incidence. We discuss optical filters designed with dielectric thin films between two right angle prisms to selectively cancel a reflected or transmitted plane wave front for different angles of incidence. A detailed analysis of these optical filters with respect to the index of refraction of the films and prisms, width of films, and polarization of light is presented. Applications on extrasolar planet detection are briefly discussed.