Edge states in self-complementary checkerboard photonic crystals: Zak phase, surface impedance and experimental verification

TL;DR

This paper theoretically analyzes and experimentally verifies the existence of deterministic edge states in self-complementary checkerboard photonic crystals, highlighting their topological origin and potential for photonic device applications.

Contribution

It introduces a method combining Zak phase analysis and surface impedance calculation to identify edge states in self-complementary photonic crystals, supported by experimental microwave verification.

Findings

Edge states exist within the common band gap of checkerboard photonic crystals.

Zak phase analysis predicts the topological nature of these edge states.

Experimental microwave measurements confirm the theoretical predictions.

Abstract

Edge states of photonic crystals have attracted much attention for the potential applications such as high transmission waveguide bends, spin dependent splitters and one-way photonic circuits. Here, we theoretically discuss and experimentally observe the deterministic edge states in checkerboard photonic crystals. Due to the self-complementarity of checkerboard photonic crystals, a common band gap is structurally protected between two photonic crystals with different unit cells. Deterministic edge states are found inside the common band gap by exploiting the Zak phase analysis and surface impedance calculation. These edge states are also confirmed by a microwave experiment.