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Going hypersound with on-chip routing

Atomic force microscopy image of acoustic fields in a SAW resonator

Phonons with frequencies in the range from a few GHz to a few tens of GHz (so-called hypersound) are particularly interesting for quantum technologies because they are resonant to many types of qubits, can be operated in the phonon ground state, and can be piezoelectrically excited. We develop technology and tools to efficiently excite and detect SAWs exceeding few GHz and 5-20 GHz BAWs. Using high-resolution scanning-probe techniques, we investigate fundamental limits of focusing and confinement of GHz SAWs and BAWs. The ability to generate and guide GHz strain will be important for on-chip transport and storage of quantum information as well as for the development of new types of compact and fast sensors.

Current focus points

  • GHz phonon lenses: We design focusing IDTs, which are used to concentrate SAWs up to 6 GHz into a small volume containing quantum systems.
  • Engineering 3D phonon fields: Bulk transducers are fabricated on the cleaved facets of semiconductor wafers, which in combination with top-side BAW transducers provides means to generate 3D acoustic lattices with sub-100 nm dimensions.
  • Phonon waveguides: In analogy with optical waveguides, we engineer structures that act as waveguides for GHz phonons.
  • Transparent electrodes: For advanced photonic applications, we develop transducers with transparent electrodes based on ITO.
  • Imaging nano-sound: We use high-resolution optical and force sensing techniques in order to obtain information about spatial distribution of acoustic waves and their amplitudes on different nano-patterned substrates.

Selected Publications

Author: M. Yuan, K. Biermann & P. V. Santos
Title: Manipulation of flying and single excitons by GHz surface acoustic waves
Source: AVS Quantum Sci. 4, 035901 (2022)

Author: A. Crespo-Poveda, A. S. Kuznetsov, A. Hernández-Mínguez, A. Tahraoui, K. Biermann, & P. V. Santos
Title: GHz guided optomechanics in planar semiconductor microcavities
Source: Optica 9, 2, 160-169 (2022)

Author: M. E. Msall & P. V. Santos
Title: Focusing surface-acoustic-wave microcavities on GaAs
Source: Phys. Rev. Applied 13, 014037 (2020)

Author: D. H. O. Machado, A. Crespo-Poveda, A. S. Kuznetsov, K. Biermann, L. V. A. Scalvi, & P. V. Santos
Title: Generation and propagation of superhigh-frequency bulk acoustic waves in GaAs
Source: Phys. Rev. Applied 12, 044013 (2019)

Author: M. Yuan , C. Hubert , S. Rauwerdink , A. Tahraoui , B von Someren , K. Biermann , P. V. Santos
Title: Generation of surface acoustic waves on doped semiconductor substrates
Source: J. Phys. D: Appl. Phys. 50, 484004 (2017)

Related Funding

  • (2018-2022) European Commission (EU) and Bundesministerium für Bildung und Forschung (BMBF) (EU-QuantERA Interpol / EU-BMBF 13N14783)
  • (2018-2022) Deutsche Forschungsgemeinschaft (426728819)