Analog signal processing through space-time digital metasurfaces

Abstract In the quest to realize analog signal processing using subwavelength metasurfaces, in this paper, we present first demonstration of programmable time-modulated metasurface processors based on key properties spatial Fourier transformation. Exploiting space-time coding strategy enables local, independent, and real-time engineering not only amplitude but also phase profile contributing reflective digital meta-atoms at both central harmonic frequencies. Several illustrative examples are demonstrated show that proposed multifunctional calculus is capable implementing a large class useful mathematical operators, including 1st- 2nd-order differentiation, 1st-order integration, integro-differential equation solving accompanied by frequency conversions. Unlike recent proposals Green’s function (GF) method, designed processor effectively operates for input signals containing wide bandwidths with an acceptable gain level. Proof-of-principle simulations reported demonstrate successful realization image functions like edge detection. This time-varying wave-based computing system can set direction future developments metasurfaces highly promising applications ultrafast solving, continuous processing, imaging.