Young's double-slit experiment with anisotropic GHz surface acoustic waves on gallium arsenide

TL;DR

This paper demonstrates a Young's double-slit experiment using GHz surface acoustic waves on gallium arsenide, revealing interference patterns affected by anisotropic wave propagation and validated by simulations.

Contribution

First implementation of Young's double-slit experiment with anisotropic GHz surface acoustic waves on GaAs, combining optical measurement and Fourier filtering techniques.

Findings

Observed clear two-slit interference patterns

Detected higher order diffraction and near field effects

Good agreement with anisotropic Huygens-Fresnel simulations

Abstract

We demonstrate Young's double-slit experiment with GHz surface acoustic waves (SAWs) on gallium arsenide (GaAs). This experiment differs from the well-known optical case due to the anisotropy of SAW propagation on GaAs. We generate SAWs using an interdigital transducer (IDT), and the double-slit is realized by focused ion beam milled grooves which block the SAWs. We measure the out-of-plane SAW displacement with an optical scanning interferometer and apply a spatial Fourier filtering technique, enabling the observation of the two-slit interference pattern, as well as higher order diffraction and near field interference effects. We find reasonable agreement between the measured far-field interference pattern and anisotropic Huygens-Fresnel simulations based on previously reported angle-dependent SAW velocities on GaAs.