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Hybrid iterative wavefront shaping for high-speed focusing through scattering media

Hemphill, Ashton S. and Wang, Lihong V. (2016) Hybrid iterative wavefront shaping for high-speed focusing through scattering media. In: Adaptive Optics and Wavefront Control for Biological Systems II. Proceedings of SPIE. No.9717. Society of Photo-Optical Instrumentation Engineers , Bellingham, WA, Art. No. 97170V. ISBN 9781628419511.

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A major limiting factor of optical imaging in biological applications is the diffusion of light by tissue, preventing focusing at depths greater than ~1 mm in the body. To overcome this issue, phase-based wavefront shaping alters the phase of sections of the incident wavefront to counteract aberrations in phase caused by scattering. This enables focusing through scattering media beyond the optical diffusion limit and increases signal compared to amplitude-based compensation. However, in previous studies, speed of optimization has typically been limited by the use of a liquid crystal spatial light modulator (SLM) for measurement and display. SLMs usually have refresh rates of less than 100 Hz and require much longer than the speckle correlation time of tissue in vivo, usually on the order of milliseconds, to determine the optimal wavefront. Here, we present a phase-based iterative wavefront shaping method based on an onaxis digital micromirror device (DMD) in conjunction with an electro-optic modulator (EOM) for measurement and a fast SLM for display. By combining phase modulation from an EOM with the modal selection of the DMD, we take advantage of DMDs higher refresh rate, approximately 23 kHz, for iterative phase measurement. The slower SLM requires one update for display following the rapid determination of the optimal wavefront via the DMD, allowing for high-speed wavefront shaping. Using this system, we are able to focus through scattering media using 64 modes in under 8 milliseconds, on the order of the speckle correlation time for tissue in vivo.

Item Type:Book Section
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Wang, Lihong V.0000-0001-9783-4383
Additional Information:© 2016 Society of Photo-Optical Instrumentation Engineers. This research was sponsored in part by National Institutes of Health grants DP1 EB016986 (NIH Director's Pioneer Award) and R01 CA186567 (NIH Director's Transformative Research Award). L. W. has a financial interest in Microphotoacoustics, Inc. and Endra, Inc. which, however, did not support this work.
Funding AgencyGrant Number
NIHDP1 EB016986
NIHR01 CA186567
Subject Keywords:Iterative Wavefront Shaping, High-Speed Wavefront Shaping, Turbid Media, Active or Adaptive Optics
Series Name:Proceedings of SPIE
Issue or Number:9717
Record Number:CaltechAUTHORS:20180905-104036816
Persistent URL:
Official Citation:Ashton S. Hemphill, Ashton S. Hemphill, Lihong V. Wang, Lihong V. Wang, } "Hybrid iterative wavefront shaping for high-speed focusing through scattering media", Proc. SPIE 9717, Adaptive Optics and Wavefront Control for Biological Systems II, 97170V (15 March 2016); doi: 10.1117/12.2211434;
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:89385
Deposited By: Tony Diaz
Deposited On:05 Sep 2018 20:49
Last Modified:16 Nov 2021 00:34

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