High Detectivity Uncooled Thermal Detectors With Resonant Cavity Coupled Absorption in the Long-Wave Infrared

摘要

We describe uncooled thermal detectors with a peak detectivity of at least $3 times 10^{9}~{rm cm} sqrt{rm Hz}/{rm W}$ with spectrally selective absorption in the long-wave infrared. The spectral selectivity in absorption is achieved through resonant cavity coupling of a thin metal film with a low-order air-gap optical cavity. The electrical readout uses thermoelectric thin films with a Johnson noise limited performance. The detectors are of multiple sizes but those with 100-$mu{rm m}^{2}$ area have time constants of 58 ms and thermal conductances of $2.3 times 10^{-7}~{rm W}/{rm K}$.