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US 5,255,075 AGranted
Optical sensor
AssigneeGEC-Marconi Limited
InventorRosemary Cush
Life of this patent
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AssigneeGEC-Marconi Limited
InventorRosemary Cush
Estimating the term…
This invention relates to an optical sensor for testing a biochemical sample. The sensor includes a resonant mirror device 1 and a prism 2 disposed adjacent the device 1 for coupling an input beam of light to the device 1. The input beam of light having a comb spectrum with a uniform spacing between adjacent lines or bands of the spectrum is produced by a comb spectrum source 10. The comb spectrum may be produced by a diode laser with multiple longitudinal modes. The input beam of light is polarized by a polarizer 4 to provide equal TE and TM components. The resonant mirror device is arranged in the paths of said input beam of light such that resonance is excited for at least one of said components, An analyser 11 is arranged to receive said components of the beam of light reflected from the device 1 for producing an output beam having a spectrum including a series of bright and/or dark lines or bands corresponding to the lines or bands of the comb spectrum of the input beam. When a sensing layer of the resonant mirror device is sensitized by the chemical sample, an angular shift in the resonance angle takes place and this causes the lines or bands of the output spectrum to be swept across a reference point where detector means 12 is located to count the number of lines or bands swept across the reference point. The angular shift in the resonance angle is equal to the product of the distance between adjacent lines of the comb spectrum and the number of lines swept across the reference point.
A method of testing a biochemical sample, the method comprising providing an optical evanescent wave sensor device having a dielectric cavity and a sensing layer, providing an input beam of light having a comb spectrum with a uniform spacing between adjacent lines or bands of the spectrum, coupling said beam of light to said device to excite resonance in said device and projecting light reflected from said device onto an analyser for producing an output beam of light having a spectrum of a series of bright and/or dark lines or bands corresponding to the lines or bands of the comb spectrum of the input beam of light, sensitizing the sensing layer by the test sample, thereby causing an angular shift in the resonance angle, said lines or bands in the output spectrum being swept across a reference point as a result of said angular shift in the resonance angle and counting said lines or bands swept across said reference point, said angular shift in the resonance angle being equal to the product of the counted number of lines or bands swept across the reference point and the distance between two adjacent lines or bands in the output spectrum.
An optical sensor for testing a biochemical sample, said sensor comprising means for providing an input beam of light having comb spectrum with a uniform spacing between adjacent lines or bands of the spectrum, an optical evanascent wave sensor device having a dielectric cavity and a sensing layer, weans for coupling said beam of light to said sensor device and projecting light reflected from said device onto an analyser for producing an output beam of light having a spectrum of a series of bright and/or dark lines or bands corresponding to the lines or bands of the comb spectrum of the input beam, said sensing layer being sensitized by the test sample, when the optical sensor is in use, thereby causing an angular shift in the resonance angle, said lines or bands in the output spectrum being swept across a reference point as a result of said angular shift in the resonance angle and means for counting said lines or bands swept across said reference point.
Dependencies are inferred from the claim text.