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O-SAM: Optical Scanning Acoustic Microscope

We have two O-SAM instruments (for historical reasons we call these the O-SAM and the ARRO-SAM). They each use a Q-switched mode locked laser to excite surface acoustic waves (SAWs), which are then detected using a CW laser. Excitation frequencies used are 82MHz and harmonics thereof. A spatial light modulator controls the distribution of light from the excitation laser, affecting the acoustic field that we generate.

The O-SAMs can be used for a wide range of experiments:

  • vector contrast imaging of Rayleigh waves
  • vector contrast imaging of Lamb waves (on thin samples)
  • thin film thickness measurement by change in SAW velocity
  • SRAS (spatially resolved acoustic spectroscopy)
  • determination of inherent material nonlinearity
  • aberration correction (adaptive acoustics, acoustic wavefront sensor) for "difficult materials"

This page will be updated with more information, but for now here's a link to a page about ultrasonic microscopy (a couple of years out of date).