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

TL;DR

This paper proposes and experimentally demonstrates a method to measure the Zak phase in photonic systems by analyzing interface states, enabling topological characterization and tunable interface states in metasurface/photonic crystal structures.

Contribution

It introduces a scheme to measure Zak phases via reflection spectra and links topological properties to interface states in photonic structures.

Findings

Successfully measured Zak phases in photonic bands.

Linked Zak phases to the existence of interface states.

Demonstrated tunability of interface states through metasurface properties.

Abstract

Zak phase labels the topological property of one-dimensional Bloch Bands. Here we propose a scheme and experimentally measure the Zak phase in a photonic system. The Zak phase of a bulk band of is related to the topological properties of the two band gaps sandwiching this band, which in turn can be inferred from the existence or absence of an interface state. Using reflection spectrum measurement, we determined the existence of interface states in the gaps, and then obtained the Zak phases. The knowledge of Zak phases can also help us predict the existence of interface states between a metasurface and a photonic crystal. By manipulating the property of the metasurface, we can further tune the excitation frequency and the polarization of the interface state.