Measurement of the Zak phase of photonic bands through the interface states of metasurface/photonic crystal

摘要

Zak phase labels the topological property of one-dimensional Bloch Bands.Here we propose a scheme and experimentally measure the Zak phase in a photonicsystem. The Zak phase of a bulk band of is related to the topologicalproperties of the two band gaps sandwiching this band, which in turn can beinferred from the existence or absence of an interface state. Using reflectionspectrum measurement, we determined the existence of interface states in thegaps, and then obtained the Zak phases. The knowledge of Zak phases can alsohelp us predict the existence of interface states between a metasurface and aphotonic crystal. By manipulating the property of the metasurface, we canfurther tune the excitation frequency and the polarization of the interfacestate.