High-impedance surface acoustic wave resonators

TL;DR

This paper presents the design and fabrication of high-impedance GHz surface acoustic wave resonators with low loss, suitable for strong coupling to quantum systems, advancing quantum interconnect technology.

Contribution

It introduces a novel high-impedance SAW resonator design with Gaussian mode confinement, achieving impedance above 100 Ω and high quality factors at millikelvin temperatures.

Findings

Impedance exceeds 100 Ω, enabling strong capacitive coupling.

Resonators maintain quality factors of several thousand at millikelvin temperatures.

Gaussian acoustic mode confinement effectively increases impedance.

Abstract

Because of their small size, low loss, and compatibility with magnetic fields and elevated temperatures, surface acoustic wave resonators hold significant potential as future quantum interconnects. Here, we design, fabricate, and characterize GHz-frequency surface acoustic wave resonators with the potential for strong capacitive coupling to nanoscale solid-state quantum systems, including semiconductor quantum dots. Strong capacitive coupling to such systems requires a large characteristic impedance, and the resonators we fabricate have impedance values above 100 $\Omega$. We achieve such high impedance values by tightly confining a Gaussian acoustic mode. At the same time, the resonators also have low loss, with quality factors of several thousand at millikelvin temperatures. These high-impedance resonators are expected to exhibit large vacuum electric-field fluctuations and have the potential for strong coupling to a variety of solid-state quantum systems.