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Time-reversed ultrasonically encoded optical focusing using two ultrasonic transducers for improved ultrasonic axial resolution

Yang, Qiang and Xu, Xiao and Lai, Puxiang and Xu, Daxiong and Wang, Lihong V. (2013) Time-reversed ultrasonically encoded optical focusing using two ultrasonic transducers for improved ultrasonic axial resolution. Journal of Biomedical Optics, 18 (11). Art. No. 110502. ISSN 1083-3668. PMCID PMC3818018.

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Focusing light inside highly scattering media is a challenging task in biomedical optical imaging, manipulation, and therapy. A recent invention has overcome this challenge by time reversing ultrasonically encoded diffuse light to an ultrasound-modulated volume inside a turbid medium. In this technique, a photorefractive (PR) crystal or polymer can be used as the phase conjugate mirror for optical time reversal. Accordingly, a relatively long ultrasound burst, whose duration matches the PR response time of the PR material, is usually used to encode the diffuse light. This long burst results in poor focusing resolution along the acoustic axis. In this work, we propose to use two intersecting ultrasound beams, emitted from two ultrasonic transducers at different frequencies, to modulate the diffuse light at the beat frequency within the intersection volume. We show that the time reversal of the light encoded at the beat frequency can converge back to the intersection volume. Experimentally, an acoustic axial resolution of ∼1.1  mm was demonstrated inside turbid media, agreeing with theoretical estimation.

Item Type:Article
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URLURL TypeDescription CentralArticle
Wang, Lihong V.0000-0001-9783-4383
Additional Information:© 2013 Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI. Paper 130680LR received Sep. 18, 2013; revised manuscript received Oct. 14, 2013; accepted for publication Oct. 18, 2013; published online Nov. 5, 2013. The authors thank Yan Liu for helpful discussions on resolution. We also thank Professor James Ballard for editing the manuscript. This work was conducted at Washington University in Saint Louis, and sponsored in part by National Academies Keck Futures Initiative grant IS 13, and National Institutes of Health grants DP1 EB016986 (NIH Director’s Pioneer Award) and U54 CA136398.
Funding AgencyGrant Number
National Academies Keck Futures InitiativeIS 13
NIHDP1 EB016986
NIHU54 CA136398
Subject Keywords:tissue optics; optical imaging; time-reversed ultrasonically encoded (TRUE) optical focusing; optical phase conjugation; photorefractive crystal
Issue or Number:11
PubMed Central ID:PMC3818018
Record Number:CaltechAUTHORS:20180905-104941380
Persistent URL:
Official Citation:Qiang Yang, Qiang Yang, Xiao Xu, Xiao Xu, Puxiang Lai, Puxiang Lai, Daxiong Xu, Daxiong Xu, Lihong V. Wang, Lihong V. Wang, } "Time-reversed ultrasonically encoded optical focusing using two ultrasonic transducers for improved ultrasonic axial resolution," Journal of Biomedical Optics 18(11), 110502 (5 November 2013).
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:89387
Deposited By: Tony Diaz
Deposited On:05 Sep 2018 20:37
Last Modified:03 Oct 2019 20:15

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