Detection beyond the standard radiation noise limit using reduced emissivity and optical cavity coupling

摘要

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.