Angular independent nonlinear transmissive filters with high Q metasurfaces

Among optical devices aimed at accelerated and energy efficient computing, metasurfaces look promising because of the large number of degrees of freedom they can access but they suffer weak nonlinearity. Here, we introduce passive and low-threshold nonlinear image filters based on local dipolar guided-mode resonant (DGMR) metasurfaces. With no incident angle dispersion over a 40° field of view, resonantly enhanced photo-thermal redshifts can switch local metasurface regions from opaque to transparent at incident intensities of just 44 μW/μm^2, with micrometer scale resolution. Such devices can serve as accelerators for digital computing and even all-optical neural networks.