Method and system for sensing and identifying foreign particles in a gaseous environment
First Claim
1. An optical system for use in sensing and identifying a foreign particle in a gaseous environment, comprising:
- a light source for generating light having a known wavelength;
an electrically-conductive opaque sheet having first and second faces opposing one another with an array of holes formed through said sheet and extending between said first and second faces, each of said holes having a diameter that is less than one quarter of said known wavelength, said sheet positioned relative to said light source such that said light is incident on said first face; and
optical detection means positioned adjacent said second face and spaced apart therefrom such that a gaseous environment is adapted to be disposed therebetween, said optical detection means detecting a light pattern at said second face when said light is incident on said first face, wherein alterations in said light pattern are indicative of the presence of a foreign particle between said first face and said optical detection means.
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Accused Products
Abstract
An optical method and system sense and identify a foreign particle in a gaseous environment. A light source generates light. An electrically-conductive sheet has an array of holes formed through the sheet. Each hole has a diameter that is less than one quarter of the light'"'"'s wavelength. The sheet is positioned relative to the light source such that the light is incident on one face of the sheet. An optical detector is positioned adjacent the sheet'"'"'s opposing face and is spaced apart therefrom such that a gaseous environment is adapted to be disposed therebetween. Alterations in the light pattern detected by the optical detector indicate the presence of a foreign particle in the holes or on the sheet, while a laser induced fluorescence (LIF) signature associated with the foreign particle indicates the identity of the foreign particle.
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Citations
28 Claims
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1. An optical system for use in sensing and identifying a foreign particle in a gaseous environment, comprising:
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a light source for generating light having a known wavelength; an electrically-conductive opaque sheet having first and second faces opposing one another with an array of holes formed through said sheet and extending between said first and second faces, each of said holes having a diameter that is less than one quarter of said known wavelength, said sheet positioned relative to said light source such that said light is incident on said first face; and optical detection means positioned adjacent said second face and spaced apart therefrom such that a gaseous environment is adapted to be disposed therebetween, said optical detection means detecting a light pattern at said second face when said light is incident on said first face, wherein alterations in said light pattern are indicative of the presence of a foreign particle between said first face and said optical detection means. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An optical system for sensing and identifying a foreign particle in a gaseous environment, comprising:
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a light source for generating light having a known wavelength; an electrically-conductive opaque sheet which has a substantially uniform thickness having first and second faces opposing one another with an array of holes formed through said sheet and extending between said first and second faces, each of said holes having a diameter that is less than one quarter of said known wavelength, said sheet defining a plane and positioned relative to said light source such that said light is incident on said first face at a substantially perpendicular angle to the plane of said sheet; optical detection means positioned adjacent said second face and spaced apart therefrom such that a gaseous environment is adapted to be disposed therebetween, said optical detection means detecting a light pattern at said second face when said light is incident on said first face, wherein alterations in said light pattern are indicative of the presence of a foreign particle between said first face and said optical detection means. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. An optical system for sensing and identifying a foreign particle in a gaseous environment comprising:
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a laser for generating laser light having a known wavelength; a substrate that is transmissive with respect to said laser light; a metallic thin-film having first and second faces opposing one another with said first face being coupled to said substrate, said metallic thin-film having an array of identically-sized holes formed therethrough and extending between said first and second faces thereof, each of said holes having a diameter that is less than one quarter of said known wavelength, said metallic thin-film positioned relative to said laser such that said laser light is incident on said first face after passing through said substrate; optical detection means positioned adjacent said second face and spaced apart therefrom such that a gaseous environment is adapted to be disposed therebetween, said optical detection means detecting a light pattern at said second face when said light is incident on said first face, wherein alterations in said light pattern are indicative of the presence of a foreign particle between said first face and said optical detection means, said optical detection means further measuring a laser induced fluorescence (LIF) signature associated with the foreign particle; and processing means coupled to said optical detection means for identifying the foreign particle using said LIF signature. - View Dependent Claims (16, 17, 18, 19, 20)
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21. A method of sensing and identifying a foreign particle in a gaseous environment, comprising:
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generating light having a known wavelength; providing an electrically-conductive opaque sheet having first and second faces opposing one another with an array of holes formed through said sheet and extending between said first and second faces, each of said holes having a diameter that is less than one quarter of said known wavelength, said sheet positioned such that said light is incident on said first face; detecting a light pattern at said second face when said light is incident on said first face, wherein alterations in said light pattern are indicative of the presence of a foreign particle between said first face and said optical detection means. - View Dependent Claims (22, 23, 24)
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25. A method of sensing and identifying a foreign particle in a gaseous environment, comprising:
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providing a metallic thin-film having a quantum aperture array formed therethrough; generating light having a known wavelength; positioning the thin-film in the light such that a surface plasmon polariton (SPP) is generated at a face of the thin-film; monitoring an emission pattern of the SPP wherein a disturbance in the emission pattern is indicative of the presence of a foreign particle. - View Dependent Claims (26, 27, 28)
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Specification