Uncooled Infrared Detector Based on an Aluminum Nitride Piezoelectric Fishnet Metasurface

This article reports on the first demonstration of a high resolution (~1.9 nW/Hz
^1/2
measured in 200 Hz bandwidth) and fast (~5.3 ms) uncooled Infrared (IR) detector based on a high frequency (172 MHz) aluminum nitride nano-plate piezoelectric fishnet-like metasurface (PFM). For the first time, an ultrathin (650 nm) piezoelectric fishnet-like metasurface is employed to form the vibrating body of a nanoelectromechanical resonator with a unique combination of optical, thermal and electromechanical properties. Sensing and actuation of a high frequency and high electromechanical performance (quality factor, Q ~2254 and electromechanical coupling coefficient, k
_t
²
~1.4%) bulk acoustic mode of vibration in the free-standing ultrathin structure is achieved thanks to the superior piezoelectric transduction properties of the proposed metasurface. Strong absorption (60%) of mid wavelength infrared (MWIR) radiation in the ultra-low volume resonant device is obtained thanks to the properly engineered optical properties of the fishnet-like metasurface which provide multiple plasmonic resonances at 3-5 μm to the structure. The demonstrated resonant PFM detector technology marks a milestone towards the implementation of a new class of high performance, miniaturized and low power MWIR imaging systems.