Reconfigurable Metasurface An input pulse with a time-modulated envelope (top) passes through a cascaded bilayer metasurface device, which imparts a mixed-order time-derivative operation on the pulse envelope function (bottom). By exploiting the twist degrees of freedom between the two layers, the mathematical operation imparted from the device can be continuously tuned between zeroth, first, and second time-differentiation. More details can be found in the Research Article by Felix Wong and Michele Cotrufo (DOI: 10.1002/adom.202502326).
Wong et al. (Sun,) studied this question.