Tamm-cavity terahertz detector

Abstract Efficiently fabricating a cavity that can achieve strong interactions between terahertz waves and matter would allow researchers to exploit the intrinsic properties due to the long wavelength in the terahertz waveband. This paper presents a terahertz detector embedded in a hybrid Tamm cavity with an extremely narrow response bandwidth and an adjustable resonant frequency. A new record has been reached: a Q value of 1017 and a bandwidth of only 469 MHz for terahertz direct detection. The hybrid Tamm-cavity detector consists of an Si/air distributed Bragg reflector (DBR), an Nb5N6 microbolometer detector on the substrate, and a metal reflector. This device enables very strong light–matter coupling by the detector with an extremely confined photonic mode compared to a Fabry–Pérot resonator detector at terahertz frequencies. Ingeniously, the substrate of the detector is used as the defect layer of the hybrid cavity. The resonant frequency can then be controlled by adjusting the thickness of the substrate cavity. The detector and DBR cavity are fabricated separately, and a large pixel-array detector can be realized by a very simple assembly process. This versatile structure can be used as a platform for preparing high-performance terahertz devices and is a breakthrough in the study of the strong interactions between terahertz waves and matter.