Presentation
15 March 2018 Applying sub-Nyquist sampling in optical time-reversal-based wavefront shaping to boost targeted light transport through opaque scattering media (Conference Presentation)
Author Affiliations +
Abstract
Wavefront shaping techniques are being actively developed to achieve optical focusing through and inside opaque scattering media. These techniques promise to revolutionize biophotonics by enabling deep-tissue non-invasive optical imaging, optogenetics, optical tweezing, and light-based therapy. Among the existing wavefront shaping techniques, optical time-reversal-based techniques determine the optimum wavefront globally based on the principle of time reversal, without the need to perform time-consuming iterations to optimize each mode in sequence. In all previous optical time-reversal-based wavefront shaping experiments, Nyquist sampling criterion was followed so that the scattered light field was well-sampled during wavefront measurement and wavefront reconstruction. In this work, we overturn this conventional practice by demonstrating that a high-quality optical focus can still be achieved even when the scattered light field is under-sampled. Even more strikingly, we show both theoretically and experimentally that the focus achieved by the under-sampling scheme can be one order of magnitude brighter than that achieved by the well-sampling schemes used in previous works, where 3×3 to 5×5 pixels sampled one speckle grain on average. Moreover, since neighboring pixels were uncorrelated in feedback-based wavefront shaping, introducing the concept of sub-Nyquist sampling in time-reversal-based wavefront shaping makes the optimal phase maps obtained using these two different methods consistent. We anticipate that this newly explored under-sampling scheme will transform the understanding of optical time reversal and boost the performance of optical imaging, manipulation, and communication through opaque scattering media.
Conference Presentation
© (2018) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Yuecheng Shen, Yan Liu, Cheng Ma, and Lihong Wang "Applying sub-Nyquist sampling in optical time-reversal-based wavefront shaping to boost targeted light transport through opaque scattering media (Conference Presentation)", Proc. SPIE 10502, Adaptive Optics and Wavefront Control for Biological Systems IV, 105020Z (15 March 2018); https://doi.org/10.1117/12.2287064
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KEYWORDS
Wavefronts

Light scattering

Biomedical optics

Opacity

Optical imaging

Scattering media

Phase conjugation

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