Real-space characterization of cavity-coupled waveguide systems in hypersonic phononic crystals

TL;DR

This paper demonstrates real-space, mode-resolved characterization of hypersonic phononic crystal cavities and waveguides, achieving high-Q resonances and single-mode transmission, advancing chip-scale phononic circuitry.

Contribution

It introduces a method for detailed real-space analysis of cavity and waveguide modes in hypersonic phononic crystals, enabling precise control and understanding.

Findings

Achieved high-Q resonances up to Q=4200 at atmospheric conditions.

Resolved single-mode wave transmission in waveguides.

Demonstrated cavity mode characterization in designed structures.

Abstract

A phononic crystal formed in a suspended membrane provides full confinement of hypersonic waves and thus realizes a range of chip-scale manipulations. In this letter, we demonstrate the mode-resolved real-space characterization of the mechanical vibration properties in cavities and waveguide systems. Multiple resonant modes are independently characterized in various designed cavities, and wavelength-scale high-$Q$ resonances up to $Q=$ 4200 under atmospheric conditions are confirmed. This also reveals that the waveguide allows us to resolve single-mode wave transmission and thereby drive evanescently-coupled cavities. The methods offer a significant tool with which to build compact and low-power microwave phononic circuitry for signal processing and hybrid quantum system applications.