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Thin-film spectroscopic sensor

  • US 5,082,629 A
  • Filed: 12/29/1989
  • Issued: 01/21/1992
  • Est. Priority Date: 12/29/1989
  • Status: Expired due to Term
First Claim
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1. An integrated spectrometer for chemical analysis by evanescent electromagnetic radiation absorption in a reaction volume, comprising:

  • a noninteractive sample waveguide having a uniform thickness and having a first surface and a second surface, and having an electromagnetic radiation entrance end and exit end, wherein the first surface communicates with the reaction volume along the region between the entrance end and exit end of the sample waveguide;

    a substrate having a top surface and a bottom surface and comprising a material characterized by allowing for the transmission of electromagnetic radiation, an entrance grating and an exit grating etched or deposited on the top surface of the substrate, such that the entrance grating communicates with the entrance end and the second surface of the waveguide and couples electromagnetic radiation into the waveguide, and the exit grating communicates with the exit end and the second surface of the waveguide and couples electromagnetic radiation out of the waveguide, wherein the gratings comprise parallel spacings and wherein the refractive index of the substrate is different from the refractive index of the waveguide;

    an electromagnetic radiation source directed toward the entrance grating; and

    an electromagnetic radiation sensing device directed toward the exit grating.

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