A Caltech Library Service

Time-reversed ultrasonically encoded optical focusing into scattering media

Xu, Xiao and Liu, Honglin and Wang, Lihong V. (2011) Time-reversed ultrasonically encoded optical focusing into scattering media. Nature Photonics, 5 (3). pp. 154-157. ISSN 1749-4885. PMCID PMC3083021.

[img] PDF - Accepted Version
See Usage Policy.

[img] Video (QuickTime) (Movie S1) - Supplemental Material
See Usage Policy.

[img] Video (QuickTime) (Movie S2) - Supplemental Material
See Usage Policy.


Use this Persistent URL to link to this item:


Light focusing plays a central role in biomedical imaging, manipulation and therapy. In scattering media, direct light focusing becomes infeasible beyond one transport mean free path. All previous methods used to overcome this diffusion limit lack a practical internal ‘guide star’. Here, we propose and experimentally validate a novel concept called time-reversed ultrasonically encoded (TRUE) optical focusing to deliver light into any dynamically defined location inside a scattering medium. First, diffused coherent light is encoded by a focused ultrasonic wave to provide a virtual internal guide star. Only the encoded light is time-reversed and transmitted back to the ultrasonic focus. The time-reversed ultrasonically encoded optical focus—defined by the ultrasonic wave—is unaffected by multiple scattering of light. Such focusing is particularly desirable in biological tissue, where ultrasonic scattering is ~1,000 times weaker than optical scattering. Various fields, including biomedical and colloidal optics, can benefit from TRUE optical focusing.

Item Type:Article
Related URLs:
URLURL TypeDescription ReadCube access CentralArticle
Liu, Honglin0000-0003-2473-9056
Wang, Lihong V.0000-0001-9783-4383
Additional Information:© 2011 Macmillan Publishers Limited. Received 20 July 2010; accepted 26 November 2010; published online 16 January 2011. This work was sponsored in part by the National Institutes of Health (grants R01 EB000712, R01 EB008085, R01 CA134539, U54 CA136398 and 5P60 DK02057933). Author contributions: X.X. and H.L. contributed equally to the experimental design and study, Monte Carlo simulation, data analysis and writing of the manuscript. L.V.W. conceived the original idea, discussed the experiments and revised the paper. The authors declare competing financial interests: L.V.W. has a financial interest in Microphotoacoustics and Endra, which, however, did not support this work.
Funding AgencyGrant Number
NIHR01 EB000712
NIHR01 EB008085
NIHR01 CA134539
NIHU54 CA136398
NIH5P60 DK02057933
Issue or Number:3
PubMed Central ID:PMC3083021
Record Number:CaltechAUTHORS:20160617-074743692
Persistent URL:
Official Citation:Time-reversed ultrasonically encoded optical focusing into scattering media Xiao Xu, Honglin Liu & Lihong V. Wang Nature Photonics 5, 154–157 (2011) doi:10.1038/nphoton.2010.306
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:68461
Deposited By: Tony Diaz
Deposited On:17 Jun 2016 18:29
Last Modified:09 Mar 2020 13:19

Repository Staff Only: item control page