DETECTION BEYOND THE STANDARD RADIATION NOISE LIMIT USING REDUCED EMISSIVITY AND OPTICAL CAVITY COUPLING
First Claim
1. A thermal detector for sensing infrared radiation, the thermal detector comprising:
- a resonant optical cavity at least partially defined by first and second spaced apart layered thin-film mirror structures; and
an infrared sensor operatively positioned between the first and second thin-film mirror structures and suspended within the resonant optical cavity by one or more electrically conductive support structures so radiation received by the resonant optical cavity impinges on at least a surface portion of the infrared sensor.
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Abstract
The present invention provides thermal detectors having an optical cavity that is optimized to couple light into a sensor. Light that is on resonance is coupled with the sensor with as high as 100% efficiency, while light off resonance is substantially reflected away. Light that strikes the sensor from the sides (i.e. not on the optical cavity axis) only interacts minimally with sensor because of the reduced absorption characteristics of the sensor. Narrowband sensors in accordance with the present invention can gain as much as 100% of the signal from one direction and spectral band, while receiving only a fraction of the normal radiation noise, which originates from all spectral bands and directions.
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Citations
21 Claims
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1. A thermal detector for sensing infrared radiation, the thermal detector comprising:
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a resonant optical cavity at least partially defined by first and second spaced apart layered thin-film mirror structures; and an infrared sensor operatively positioned between the first and second thin-film mirror structures and suspended within the resonant optical cavity by one or more electrically conductive support structures so radiation received by the resonant optical cavity impinges on at least a surface portion of the infrared sensor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A thermal detector for sensing infrared radiation, the thermal detector comprising:
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a resonant optical cavity at least partially defined by first and second spaced apart layered thin-film mirror structures; and an infrared sensor operatively positioned between the first and second thin-film mirror structures and suspended within the resonant optical cavity by one or more electrically conductive support structures so radiation received by the resonant optical cavity impinges on at least a portion of the infrared sensor and wherein said portion of the infrared sensor has an absorption less than or equal to twenty-five percent. - View Dependent Claims (14, 15, 16, 17, 18)
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19. A method of sensing infrared radiation, the method comprising the steps of
providing a resonant optical cavity at least partially defined by first and second spaced apart mirror thin-film structures and an infrared sensor suspended within the resonant optical cavity; -
causing radiation to enter the resonant optical cavity and couple with the infrared sensor; and measuring a change in the infrared sensor caused by the radiation coupled with the infrared sensor. - View Dependent Claims (20)
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21-25. -25. (canceled)
Specification