Digital Holographic microscopy for surface and bulk acoustic waves imaging

Partner Call open until: May 21, 2021

Start of the project: July 1, 2021


This project aims to develop a characterization setup for surface and bulk acoustic waves imaging for the quality control and development of 5G and 6G RF filters. The existing setup developed at SAL is based on scanning heterodyne interferometry, which limits the acquisition speed of the acoustic field. This project aims at the implementation of a full-field digital holographic microscopy approach that will enable higher performance and new possibilities in the high frequency MEMS characterization, and the demonstration of the latter on state-of-the-art RF filters.

The main objectives include:

  • Functioning imaging of surface and bulk acoustic waves
    • Up to 8 GHz excitation frequency
    • Sub-picometer amplitude resolution in a few seconds
    • High resolution for the characterization high Q factor resonators
  • Demonstration of the capability on RF devices
  • Low frequency compatibility down to 25 MHz for sub-RF MEMS devices


The key challenge include:

  • Optical design of the interferometer
  • Picosecond laser feed into the imaging head
  • Picosecond laser synchronization to the MEMS actuation


The research topics include:

  • Short pulse optics, picosecond fiber optics
  • RF design, synchronization
  • High frequency MEMS, surface and bulk acoustic wave devices

Expected Results

  • A functional setup
  • Images of the acoustic field of actuated state-of-the-art RF devices
  • Setup specification, design diagrams
  • Invention disclosures or patents and know-how
  • Publications, conference abstracts, posters, and presentations