Detection beyond the standard radiation noise limit using spectrally selective absorption
First Claim
1. A thermal detector for sensing infrared radiation comprising an infrared absorber that is spectrally selective, the absorber suspended by one or more electrically conductive support structures so incoming radiation impinges on at least a portion of the infrared absorber and wherein said portion of the infrared absorber absorbs strongly in a desired spectral wavelength region and weakly in a second spectral wavelength region that corresponds with the primary thermal emission region for that temperature.
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Abstract
High sensitivity thermal detectors that perform beyond the blackbody radiation noise limit are described. Thermal detectors, as described herein, use spectrally selective materials that absorb strongly in the wavelength region of the desired signal but only weakly or not at all in the primary thermal emission band. Exemplary devices that can be made in accordance with the present invention include microbolometers containing semiconductors that absorb in the MWIR and/or THz range but not the LWIR.
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Citations
22 Claims
- 1. A thermal detector for sensing infrared radiation comprising an infrared absorber that is spectrally selective, the absorber suspended by one or more electrically conductive support structures so incoming radiation impinges on at least a portion of the infrared absorber and wherein said portion of the infrared absorber absorbs strongly in a desired spectral wavelength region and weakly in a second spectral wavelength region that corresponds with the primary thermal emission region for that temperature.
- 11. A microbolometer comprising an absorber that is spectrally selective, the absorber comprising a semiconductor absorber layer and a TCR layer, with both layers having a bandgap or absorption bands that absorbs incoming radiation in one or more of the SWIR, MWIR, and THz spectral regions more strongly than the semiconductor absorber layer absorbs incoming radiation in the LWIR spectral region.
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15. A broadband thermal detector for sensing one or more of MWIR and THz radiation comprising detectivity greater than 2×
- 1010 cmHz1/2/W.
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16. A method of sensing infrared radiation comprising providing an absorber that is spectrally selective and selectively absorbing incoming radiation of a desired spectral wavelength region more strongly than radiation in a second spectral wavelength region that corresponds with the primary thermal emission region to provide a detectivity of the sensor greater than 2×
- 1010 cmHz1/2/W.
- View Dependent Claims (17, 18, 19, 20, 21, 22)
Specification