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Focusing light inside dynamic scattering media with millisecond digital optical phase conjugation

Liu, Yan and Ma, Cheng and Shen, Yuecheng and Wang, Lihong V. (2017) Focusing light inside dynamic scattering media with millisecond digital optical phase conjugation. In: Adaptive Optics and Wavefront Control for Biological Systems III. Proceedings of SPIE. No.10073. Society of Photo-Optical Instrumentation Engineers , Bellingham, WA, Art. No. 100730F . ISBN 9781510605879.

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Optical phase conjugation based wavefront shaping techniques are being actively developed to focus light through or inside scattering media such as biological tissue, and they promise to revolutionize optical imaging, manipulation, and therapy. The speed of digital optical phase conjugation (DOPC) has been limited by the low speeds of cameras and spatial light modulators (SLMs), preventing DOPC from being applied to thick living tissue. Recently, a fast DOPC system was developed based on a single-shot wavefront measurement method, a field programmable gate array (FPGA) for data processing, and a digital micromirror device (DMD) for fast modulation. However, this system has the following limitations. First, the reported single-shot wavefront measurement method does not work when our goal is to focus light inside, instead of through, scattering media. Second, the DMD performed binary amplitude modulation, which resulted in a lower focusing contrast compared with that of phase modulations. Third, the optical fluence threshold causing DMDs to malfunction under pulsed laser illumination is lower than that of liquid crystal based SLMs, and the system alignment is significantly complicated by the oblique reflection angle of the DMD. Here, we developed a simple but high-speed DOPC system using a ferroelectric liquid crystal based SLM (512 × 512 pixels), and focused light through three diffusers within 4.7 ms. Using focused-ultrasound-guided DOPC along with a double exposure scheme, we focused light inside a scattering medium containing two diffusers within 7.7 ms, thus achieving the fastest digital time-reversed ultrasonically encoded (TRUE) optical focusing to date.

Item Type:Book Section
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URLURL TypeDescription ItemJournal Article
Liu, Yan0000-0002-5837-4908
Shen, Yuecheng0000-0003-1990-8142
Wang, Lihong V.0000-0001-9783-4383
Additional Information:© 2017 Society of Photo-Optical Instrumentation Engineers.
Series Name:Proceedings of SPIE
Issue or Number:10073
Record Number:CaltechAUTHORS:20180907-104553848
Persistent URL:
Official Citation:Yan Liu, Yan Liu, Cheng Ma, Cheng Ma, Yuecheng Shen, Yuecheng Shen, Lihong V. Wang, Lihong V. Wang, } "Focusing light inside dynamic scattering media with millisecond digital optical phase conjugation (Conference Presentation)", Proc. SPIE 10073, Adaptive Optics and Wavefront Control for Biological Systems III, 100730F (24 April 2017); doi: 10.1117/12.2250042;
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:89460
Deposited By: Tony Diaz
Deposited On:10 Sep 2018 19:52
Last Modified:16 Nov 2021 00:35

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