Zero phase delay induced by wavefront modulation in photonic crystals

摘要

A new mechanism for the generation of efficient zero phase delay of electromagnetic wave propagation based on wavefront modulation is investigated in this paper. Both numerical simulations and experiments have demonstrated the zero phase delay behaviors of wave propagation in a two-dimensional triangular photonic crystal. The zero phase delay propagation, independent of the propagating distance, is attributed to an invariable wavefront modulation in a photonic crystal in the direction of wave propagation where the phase velocity is perpendicular to the group velocity with parallel wavefronts (or phasefronts) extending along the direction of the energy flow. This effect can be extended to the three-dimensional cases or other artificially engineered materials and may open a new route for obtaining perfect zero phase delay propagation for an electromagnetic wave instead of using zero-index or zero-averaged-index materials and may have significant potential in many applications.