Method for extracting the equivalent admittance from time-varying metasurfaces and its application to self-tuned spatiotemporal wave manipulation

Abstract With their self-tuned time-varying responses, waveform-selective metasurfaces embedded with nonlinear electronics have shown fascinating applications, including distinguishing different electromagnetic waves depending on the pulse width (PW). However, thus far they only been realized a spatially homogeneous scattering profile. Here, by modeling metasurface as admittance sheets, we provide an analytical calculation method to predict time-domain responses. This allows derivation of design specifications in form equivalent sheet admittance, which is useful synthesizing spatiotemporal control, such realize prescribed time-dependent diffraction characteristics. As example, based proposed modeling, synthesize Fresnel zone plate variable focal length incoming PW. The synthesis for PW-dependent may be extended designing more complex wave manipulation, benefiting applications sensing, wireless communications and signal processing.