Resonant infrared detector based on a piezoelectric fishnet metasurface

This paper reports on the first demonstration of a high resolution (noise equivalent power NEP of 1.9 nW/Hz^1/2 at 200 Hz bandwidth) and fast (thermal time constant of 5.3 ms) infrared (IR) detector based on a nanoelectromechanical system (NEMS) resonant 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 nanomechanical resonator with a unique combination of optical, thermal and electromechanical properties. Efficient sensing and actuation (electromechanical coupling coefficient, k_t²~1.4%) of a high frequency (172 MHz) and high quality factor (Q~2254) 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 short wavelength infrared (SWIR) radiation in the ultra-low volume resonant device is obtained thanks to the properly engineered optical properties of the fishnet-like metasurface which provide a Fabry-Perot like resonance at ~4 μm to the structure.