Patent ID: 6859483

Claim:
An optical filter comprising: a metal layer; a dielectric spacer layer deposited on said metal layer; and a dielectric stack of alternating relatively high and low refractive index layers deposited on said spacer layer; wherein a first thickness of said dielectric spacer layer and a second thickness of each of said high and low refractive index layers is selected such that incident radiation of wavelengths inside a predetermined resonant wavelength band is substantially transmitted through the dielectric stack and the spacer layer to the metal layer, and incident radiation of wavelengths outside the predetermined resonant wavelength band is substantially reflected from interfaces between said relatively high and low refractive index layers of said dielectric stack; and wherein the metal layer is opaque to incident radiation inside said predetermined resonant wavelength band, such that incident radiation transmitted through the dielectric spacer layer is channeled into and absorbed by the metal layer, and none of the incident radiation is transmitted through the metal layer.