Reflection-mode timereversed ultrasonically encoded optical focusing into turbid media

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

Research output: Journal article publicationJournal articleAcademic researchpeer-review

42 Citations (Scopus)


Time-reversed ultrasonically encoded (TRUE) optical focusing was recently proposed to deliver light dynamically to a tight region inside a scattering medium. In this letter, we report the first development of a reflection-mode TRUE optical focusing system. A high numerical aperture light guide is used to transmit the diffusely reflected light from a turbid medium to a phase-conjugate mirror (PCM), which is sensitive only to the ultrasound-tagged light. From the PCM, a phase conjugated wavefront of the tagged light is generated and conveyed by the same light guide back to the turbid medium, subsequently converging to the ultrasonic focal zone. We present experimental results from this system, which has the ability to focus light in a highly scattering medium with a round-trip optical penetration thickness (extinction coefficient multiplied by round-trip depth) as large as 160.
Original languageEnglish
Article number080505
JournalJournal of Biomedical Optics
Issue number8
Publication statusPublished - 1 Aug 2011
Externally publishedYes


  • Optical focusing
  • Optical imaging
  • Optical phase conjugation
  • Photorefractive crystal
  • Reflection mode
  • Time reversal
  • Turbid media
  • Ultrasonic modulation

ASJC Scopus subject areas

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


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