Time-reversed ultrasonically encoded optical focusing in biological tissue

Puxiang Lai, Xiao Xu, Honglin Liu, Lihong V. Wang

Research output: Journal article publicationJournal articleAcademic researchpeer-review

30 Citations (Scopus)


We report an experimental investigation of timereversed ultrasonically encoded optical focusing in biological tissue. This technology combines the concepts of optical phase conjugation and ultrasound modulation of diffused coherent light. The ultrasonically encoded (or tagged) diffused light from a tissue sample is collected in reflection mode and interferes with a reference light in a photorefractive crystal (used as a phase conjugation mirror) to form a hologram. Then a time-reversed copy of the tagged light is generated and traces back the original trajectories to the ultrasonic focus inside the tissue sample. With our current setup, we can achieve a maximum penetration depth of 5 mm in a chicken breast sample and image optical contrasts within a tissue sample with a spatial resolution approximately equaling 1/√2 of the ultrasound focal diameter.
Original languageEnglish
Article number030506
JournalJournal of Biomedical Optics
Issue number3
Publication statusPublished - 1 Mar 2012
Externally publishedYes


  • Biological tissue
  • Optical focusing
  • Optical imaging
  • Optical phase conjugation
  • Photorefractive crystal
  • Reflection mode
  • Time reversal
  • Ultrasound modulation

ASJC Scopus subject areas

  • Biomedical Engineering
  • Biomaterials
  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics


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