Plasmonic Metasurface "Bullets" and other "Moving Objects": Spatiotemporal Dispersion Cancellation for Linear Passive Subwavelength Slow Light.

A class of plasmonic metasurfaces is introduced with the ability to tailor the dispersion surface of the associated plasmon-polariton into striking novel shapes. Examples include dispersion surfaces with hyperbolic curves, with multiple van Hove singularities of various types or with points of simultaneous spatiotemporal dispersion cancellation leading to unprecedented surface flatness. The latter effect, unseen before in linear passive systems, implies slow propagation of ultrasubwavelength wave packets of any shape devoid of longitudinal or lateral broadening, limited only by absorption.