Uncooled, high sensitivity spectral selective infrared detector

An infrared (IR) detector comprises a radio frequency (RF) resonator including a bottom electrode to provide acoustic excitation, a piezoelectric layer connected to the bottom electrode and suspended over a cavity defined within a semiconductor substrate, and a top layer comprising a mid-IR metamaterial and which is connected to the piezoelectric layer of the RF resonator. The top layer and the piezoelectric layer are sized to impedance match with a particular IR wavelength, to minimize reflection and maximize absorption of a particular IR wavelength, and thus make the top layer polarization sensitive to the particular IR wavelength.