Tunable Fabry-Perot filter
AssigneeHoneywell Inc.
InventorsWilliam W. Durand, Ronald E. Peterson
Life of this patent
Estimating the term…
Abstract
A tunable Fabry-Perot filter for transmitting light in the wavelength range from 3-40 microns is disclosed wherein a pair of low index substrates of refractive index less than 2.4 and positioned between an adjustable spacer means have, on their facing sides, a non-metallic coating of refractive index of at least 4.0 and of optical thickness less than one-half the minimum wavelength to be transmitted. Preferred substrates are potassium halides, cesium halides, and zinc selenide, and preferred high index coatings are from the group of lead telluride, bismuth telluride, germanium telluride and germanium.
Claims6
A tunable Fabry-Perot filter device, comprising:
- a pair of low index substrates having a refractive index of less than 2.4 and mounted in parallel relationship so as to present facing sides to each other in an optical path;
- a high index, non-metallic coating having a refractive index of at least 4.0 and an optical thickness less than one half of the minimum wavelength to be transmitted, said high index coating being on said facing sides of each said low index substrates;
- and
- spacer means for mounting said low index substrates and for adjusting the distance between said facing sides.
A pair of low index substrates having a refractive index of less than 2.4 and mounted in parallel relationship so as to present facing sides to each other in an optical path;
- a high index non-metallic coating which is less than ten percent absorbing in the 3 to 40 micron wavelength range and has a refractive index of at least 4.0 and an optical thickness less than one half of the minimum wavelength to be transmitted, said high index coating being on said facing sides of each said low index substrates;
- and
- spacer means for mounting said low index substrates and for adjusting the distance between said facing sides.
Dependencies are inferred from the claim text.