Room-Temperature Mid-Infrared Detection via Resonant Microwave Circuits

We demonstrate a room-temperature mid-wave infrared MWIR <; 5 μm) photoconductive detection architecture utilizing a compact, Ku-band microwave split-ring resonator (SRR) loaded with a micrometer-scale indium arsenide antimonide (InAsSb) pixel. The resonant microwave photoconductor (RMPC) does not require the fabrication of ohmic contacts or the need for dc current collection. We compare the RMPC architecture with a traditional dc photoconductor (DCPC) and evaluate the conditions in which the overall sensitivity of the RMPC exceeds that of the DCPC. Time-domain simulations suggest that the resonator can shape and suppress the fundamental Johnson thermal noise of the semiconductor photon-absorbing element, resulting in decreased total noise and thus increased detectivity, with the SRR circuit itself being the primary generator of thermal noise. For this material system, we calculate that the RMPC has a factor of three improvement in the overall Johnson-limited detectivity (D*) when compared to the standard DCPC and discuss both the situations for which this improvement could be significantly larger as well as practical system noise considerations.