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Published March 10, 2015 | Published + Supplemental Material
Journal Article Open

Analog time-reversed ultrasonically encoded light focusing inside scattering media with a 33,000x optical power gain


Recent breakthrough in wavefront engineering shows great promises in controlling light propagation inside scattering media. At present, the digital approaches enjoy high gain, while their speeds are slow because of high data throughputs. In contrast, the analog approaches are intrinsically fast but suffer from poor efficiencies and small gains. Further improvements in both speed and gain are necessary to advance the existing technologies toward real-world applications. Here, we report analog time-reversal of acousto-optically tagged photons with a flux amplification of over 33,000 times (45 dB) at a target location inside scattering media. Such a substantial power gain enhancement is achieved when the temporal width of the time-reversed photon packet is squeezed below the carrier-recombination-limited hologram decay time in a photorefractive crystal. Despite a focusing energy gain below unity, the unprecedented power gain is expected to enable new optical imaging, sensing, manipulation and treatment applications.

Additional Information

© 2016 Macmillan Publishers Limited. This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article's Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder in order to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ Received: 12 October 2014; Accepted: 05 February 2015; Published online: 10 March 2015. The authors appreciate Yan Liu, Sandra Matteucci and Jim Ballard's help with editing the manuscript. We wish to thank Yan Liu, Puxiang Lai and Jean-Pierre Huignard for inspiring discussions. This work was supported by National Institutes of Health grant DP1 EB016986 (NIH Director's Pioneer Award). Author contributions: C.M. and L.V.W. initiated the project. C.M. and X.X. implemented the system. C.M. ran the experiments, performed the simulation, and processed the experimental results. L.V.W. provided overall supervision. All authors involved in writing the manuscript. The authors declare no competing financial interests.

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Published - srep08896.pdf

Supplemental Material - srep08896-s1.pdf


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