Temporal interfaces in time-modulated metasurface for the excitation of space-time wave packets

Space-time wave packets (STWPs) are a class of polychromatic field configurations that do not experience diffraction as they propagate. This property is given by their peculiar spatialtemporal light structure that satisfies a one-to-one correlation between spatial and temporal frequencies, making their excitation constrained to the use of complex launchers. To overcome these challenges in excitation, in this contribution, we exploit the temporal scattering properties of a surface wave propagating along a metasurface that abruptly switches its surface impedance. We demonstrate that the surface wave couples with free-space radiation as a nondiffracting field satisfying the properties of a space-time wave packet. Analytical formulation and numerical simulations are provided to verify the STWP-like propagation.