How Do Space-Time Digital Metasurfaces Serve to Perform Analog Signal Processing?
Abstract
In the quest to realize analog signal processing using sub-wavelength metasurfaces, in this paper, we demonstrate the first experimental demonstration of programmable time-modulated metasurface processors based on the key properties of spatial Fourier transformation. Exploiting space-time coding strategy enables local, independent, and real-time engineering of not only amplitude but also phase profile of the contributing reflective digital meta-atoms at both central and harmonic frequencies. Several illustrative examples are demonstrated to show that the proposed multifunctional calculus metasurface is capable of implementing a large class of useful mathematical operators, including 1st- and 2nd-order spatial differentiation, 1st-order spatial integration, and integro-differential equation solving accompanied by frequency conversions. Unlike the recent proposals, the designed time-modulated signal processor effectively operates for input signals containing wide spatial frequency bandwidths with an acceptable gain level. Proof-of-principle simulations are also reported along with the successful realization of image processing functions like edge detection. This time-varying wave-based computing system can set the direction for future developments of programmable metasurfaces with highly promising applications in ultrafast equation solving, real-time and continuous signal processing, and imaging.
Cite
@article{arxiv.2002.06773,
title = {How Do Space-Time Digital Metasurfaces Serve to Perform Analog Signal Processing?},
author = {Hamid Rajabalipanah and Ali Abdolali and Shahid Iqbal and Lei Zhang and Tie Jun Cui},
journal= {arXiv preprint arXiv:2002.06773},
year = {2020}
}
Comments
24 pages, 9 figures