Optical sensor for selective detection of substances and/or for the detection of refractive index changes in gaseous, liquid, solid and porous samples
DCFirst Claim
1. An optical sensor for detecting chemical, biochemical or biological substances in a sample, comprising:
- a waveguiding structure formed by a waveguiding film covering a substrate, wherein the waveguiding film has a refractive index at least 1% higher than the refractive index of the substrate;
a diffraction grating contained in the waveguiding structure; and
a chemo-responsive layer covering the waveguiding film in a region around the diffraction grating, wherein said chemo-responsive layer is capable of binding with the substances to be assayed and has a thickness of less than one wavelength.
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Abstract
The optical sensor for the detection of specific substances and refractive index changes in gaseous, liquid, solid and porous samples is composed of integrated optical elements. It consists of a waveguiding film (1) equipped with a diffraction grating (4) and applied onto a substrate (2). For the selective detection of a specific substance contained in the sample (3) a selectively chemisorbing additional layer (5) covers the film (1) at least in the grating region. The sample (3) is applied at least in the grating region either directly onto the waveguiding film (1) or onto the selectively chemisorbing additional layer (5). Chemisorption of the substance, which is contained in the sample (3) and is to be detected, to the selectively chemisorbing additional layer (5) results in a further adlayer (6) coating the waveguiding film (1). The principle of the sensor is as follows: Due to chemisorption of a further adlayer (6) and/or due to a refractive index change of the sample (3) a change in the effective refractive index N of a mode guided in the waveguiding film (1) is effected. For the detection of this change the set-up (1,2,3,4,5) described above is used as grating coupler or Bragg reflector.
457 Citations
31 Claims
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1. An optical sensor for detecting chemical, biochemical or biological substances in a sample, comprising:
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a waveguiding structure formed by a waveguiding film covering a substrate, wherein the waveguiding film has a refractive index at least 1% higher than the refractive index of the substrate; a diffraction grating contained in the waveguiding structure; and a chemo-responsive layer covering the waveguiding film in a region around the diffraction grating, wherein said chemo-responsive layer is capable of binding with the substances to be assayed and has a thickness of less than one wavelength. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A method for detecting chemical, biochemical or biological substances in a sample including the steps of:
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measuring the effective index of an optical sensor comprising a waveguiding structure formed by a waveguiding film covering a substrate wherein the waveguiding film has a refractive index at least 1% higher than the refractive index of the substrate, a diffraction grating in said waveguiding structure, and a chemo-responsive layer covering the waveguiding film in a region around the diffraction grating so that the chemo-responsive layer is capable of binding the substances to be assayed and has a thickness of less than one wavelength;
contacting said optical sensor with the sample; and
measuring the effective index change caused by the binding of the species to the chemo-responsive layer. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30, 31)
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Specification