All-optical adaptive scanning acoustic microscope

Steve D. Sharples, Matt Clark, Michael Geoffrey Somekh

Research output: Journal article publicationJournal articleAcademic researchpeer-review

24 Citations (Scopus)

Abstract

We have constructed a fast laser-based surface acoustic wave (SAW) microscope, which may be thought of as a non-perturbing scanning acoustic microscope. The instrument is capable of rapid high resolution vector contrast imaging at several discrete frequencies, without any damage to the sample. Tailoring the generating optical distribution using computer-generated holograms allows us to both focus the acoustic waves (increasing their amplitude) and to spread the optical power over the sample surface (preventing damage). Accurate quantitative amplitude and phase (velocity) measurements and unique acoustic contrast mechanisms are possible with our instrument based on this technology due to the non-perturbing nature and the instrument geometries. However, the complexity of the optical generation profile leads to a strong dependence on material properties such as the SAW velocity and material anisotropy. We address these issues in this paper, and demonstrate how a spatial light modulator may be used to adapt the generating optical distribution to compensate for the material properties. This facilitates simpler alignment and velocity matching, and, combined with an acoustic wavefront sensor, will allow real-time adjustment of the generating source to enable imaging on anisotropic materials.
Original languageEnglish
Pages (from-to)295-299
Number of pages5
JournalUltrasonics
Volume41
Issue number4
DOIs
Publication statusPublished - 1 Jun 2003
Externally publishedYes

Keywords

  • Adaptive acoustics
  • Laser ultrasonics
  • Scanning acoustic microscope
  • Spatial light modulator
  • Vector contrast imaging

ASJC Scopus subject areas

  • Medicine(all)
  • Acoustics and Ultrasonics

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