Chalcogenide Metasurfaces Enabling Ultra-Wideband Detectors From Visible to Mid-infrared

Thermoelectric materials can be designed to support optical resonances across multiple spectral ranges to enable ultra-wideband photodetection. For instance, antimony telluride (Sb₂Te₃) chalcogenide exhibits interband plasmonic resonances in the visible range and Mie resonances in the mid-infrared (mid-IR) range, while simultaneously possessing large thermoelectric Seebeck coefficients of 178 µV K^-1. However, chalcogenide metasurfaces for achieving miniaturized and wavelength-sensitive ultra-wideband detectors have not been explored so far, especially with a single material platform. In this paper, Sb₂Te₃ metasurface devices are designed and fabricated to achieve ≈97% resonant absorption for enabling photodetectors operating across an ultra-wideband spectrum, from visible to mid-IR. Furthermore, relying on linear polarization-sensitive Sb₂Te₃ metasurface, the thermoelectric photodetectors with linear polarization-selectivity are demonstrated. This work provides a potential platform toward the portable ultrawide band spectrometers without requiring cryogenic cooling, for environmental sensing applications.