The angle-dependent phase velocity of GHz acoustic waves in GaAs

Surface acoustic waves (SAWs) in gallium arsenide (GaAs) are promising carriers of quantum information and can couple to various quantum systems such as quantum dots. This coupling between acoustic waves and quantum dots can be enhanced using focused cavities. Due to the anisotropy of the acoustic wave velocity on GaAs, the mirror shape of focusing cavities needs to be adapted to the wavefront. In this project, we measure the angle-dependent phase velocity v(θ) of acoustic wave modes in GaAs at GHz frequency, using a high-precision interferometric setup that captures the amplitude and phase of the acoustic displacement. To separate the acoustic modes by their spatial periodicities, we perform a spatial Fast Fourier transform (FFT) and extract the modes using ridge detection. We use the found spatial frequencies to calculate the angle dependent phase velocity. To our knowledge, this is the first study to combine full angle-resolved phase velocity measurements of surface and bulk...Show moreSurface acoustic waves (SAWs) in gallium arsenide (GaAs) are promising carriers of quantum information and can couple to various quantum systems such as quantum dots. This coupling between acoustic waves and quantum dots can be enhanced using focused cavities. Due to the anisotropy of the acoustic wave velocity on GaAs, the mirror shape of focusing cavities needs to be adapted to the wavefront. In this project, we measure the angle-dependent phase velocity v(θ) of acoustic wave modes in GaAs at GHz frequency, using a high-precision interferometric setup that captures the amplitude and phase of the acoustic displacement. To separate the acoustic modes by their spatial periodicities, we perform a spatial Fast Fourier transform (FFT) and extract the modes using ridge detection. We use the found spatial frequencies to calculate the angle dependent phase velocity. To our knowledge, this is the first study to combine full angle-resolved phase velocity measurements of surface and bulk modes simultaneously and the results show good agreement with the theoretical model.Show less

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The angle-dependent phase velocity of GHz acoustic waves in GaAs