Rectifying infrared metasurfaces and diodes for sensing

Sensors are limited by semiconducting bandgaps and rigid wavelength cutoffs. Lower priced, attritable manufacturable detectors are needed for Uncrewed Aerial Vehicle missions. We present our results from 6 publications and new theory: nonlinear optical rectification (OR) currents flow in inversion-symmetry breaking plasmonic gratings and metasurfaces exhibiting Extraordinary Optical Transmission (EOT) with periodicities of 1200 – 1488 nm, via surface plasmonic-polariton (SPP) resonances excited by near-infrared laser photons. The incident linearly polarized electric field excites 2 SPPs perpendicular to the grating (x-axis). Asymmetry of the grating enabled asymmetric SPP excitation/diffraction and DC current/voltage both longitudinal and transverse to the plane of incidence. The helicity of the incident photon selects the preferred SPP direction based on optimum spin-momentum coupling (SML) of the SPP transverse spin to the photon momentum or the coupling of the photon spin to the SPP momenta. Such a sensitive detector could optimally track a laser, whose tilt and rotation angles with respect to the receiver vary due to turbulence, pointing drift, atmospheric lensing, etc.