We report the design of silica-based 1D phononic crystals (PnCs) with topologically distinct complete phononic bandgaps (PnBGs) and the observation of a topologically protected state of elastic waves at their interface. By choosing different structural parameters of unit cells, two PnCs can possess a common PnBG with different topological nature. At the interface between the two PnCs, a topological interface mode with a quality factor of ~5,650 is observed in the PnBG. Spatial confinement of the interface mode is also confirmed by using photoelastic imaging technique. Such topologically protected elastic states are potentially applicable for constructing novel phononic devices.
@article{arxiv.1710.05471,
title = {Topologically protected elastic waves in one-dimensional phononic crystals of continuous media},
author = {Ingi Kim and Satoshi Iwamoto and Yasuhiko Arakawa},
journal= {arXiv preprint arXiv:1710.05471},
year = {2017}
}