Sub-Nyquist sampling boosts targeted light transport through opaque scattering media.
Sub-Nyquist sampling boosts targeted light transport through opaque scattering media.
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DOI：
10.1364/optica.4.000097
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发表时间：
2017-01-20
期刊：
影响因子：
10.4
通讯作者：
Wang LV
中科院分区：
文献类型：
--
作者：
Shen Y;Liu Y;Ma C;Wang LV
光学时间反转技术正在积极发展，以聚焦光通过或内部不透明的散射介质。当应用于生物组织时，这些技术有望通过实现深层组织非侵入性光学成像、光遗传学、光学镊子和光疗来彻底改变生物光子学。在以往的光学时间反演实验中，在波前测量和波前重建过程中，散射光场都是按照奈奎斯特采样准则进行良好采样的。在这里，我们通过证明即使当散射场欠采样时，光仍然可以通过散射介质或散射介质内部聚焦来推翻这种传统做法。更令人惊讶的是，我们从理论上和实验上表明，通过欠采样实现的焦点可以比在以前的作品中使用的良好采样条件下实现的焦点亮一个数量级，其中平均使用3×3到5×5像素来采样一个散斑颗粒。此外，次奈奎斯特采样提高了散射光的信噪比和收集效率。我们预计，这种新探索的欠采样方案将改变对光学时间反演的理解，并通过不透明的散射介质提高光学成像，操纵和通信的性能。
Optical time-reversal techniques are being actively developed to focus light through or inside opaque scattering media. When applied to biological tissue, these techniques promise to revolutionize biophotonics by enabling deep-tissue non-invasive optical imaging, optogenetics, optical tweezing, and phototherapy. In all previous optical time-reversal experiments, the scattered light field was well-sampled during wavefront measurement and wavefront reconstruction, following the Nyquist sampling criterion. Here, we overturn this conventional practice by demonstrating that even when the scattered field is under-sampled, light can still be focused through or inside scattering media. Even more surprisingly, we show both theoretically and experimentally that the focus achieved by under-sampling can be one order of magnitude brighter than that achieved under the well-sampling conditions used in previous works, where 3×3 to 5×5 pixels were used to sample one speckle grain on average. Moreover, sub-Nyquist sampling improves the signal-to-noise ratio and the collection efficiency of the scattered light. 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.