Visualization of Gaussian Mode Profile in Gigahertz Surface-Acoustic-Wave Resonators

TL;DR

This paper demonstrates the visualization of Gaussian acoustic mode profiles in GHz SAW resonators using transmission-mode microwave impedance microscopy, aiding in device optimization for telecommunications and quantum applications.

Contribution

It introduces a microscopy technique to directly image and analyze the mode profiles and imperfections of GHz SAW resonators, advancing their microscopic understanding.

Findings

Gaussian mode profiles are vividly visualized in TMIM images.

Linewidths of resonators can be extracted from the images.

Failure analysis of faulty devices is enabled through spatially resolved profiles.

Abstract

Surface-acoustic-wave (SAW) resonators operating at gigahertz (GHz) frequencies are widely used in wireless telecommunication and quantum information processing. Successful implementation of such resonators calls for detailed microscopic understanding of their mode profiles, energy dissipation channels, and imperfections from microfabrication. In this work, we report on the visualization of acoustic waves in LiNbO3 SAW resonators by transmission-mode microwave impedance microscopy (TMIM). The Gaussian mode profile tightly confined by reflecting mirrors is vividly seen in the TMIM images, from which the linewidth of the resonator itself can be extracted. The spatially resolved acoustic profile also allows us to perform failure analysis on faulty devices. Our work establishes a pathway for further optimization of SAW resonators for classical and quantum acoustic applications.