Polonschii Cristina, Gheorghiu Mihaela, David Sorin, Gáspár Szilveszter, Melinte Sorin, Majeed Hassaan, Kandel Mikhail E, Popescu Gabriel, Gheorghiu Eugen
International Centre of Biodynamics, 060101, Bucharest, Romania.
Institute of Information and Communication Technologies, Electronics and Applied Mathematics, Université Catholique de Louvain, 1348, Louvain-la-Neuve, Belgium.
Light Sci Appl. 2021 Jan 21;10(1):20. doi: 10.1038/s41377-020-00461-x.
Retrieving electrical impedance maps at the nanoscale rapidly via nondestructive inspection with a high signal-to-noise ratio is an unmet need, likely to impact various applications from biomedicine to energy conversion. In this study, we develop a multimodal functional imaging instrument that is characterized by the dual capability of impedance mapping and phase quantitation, high spatial resolution, and low temporal noise. To achieve this, we advance a quantitative phase imaging system, referred to as epi-magnified image spatial spectrum microscopy combined with electrical actuation, to provide complementary maps of the optical path and electrical impedance. We demonstrate our system with high-resolution maps of optical path differences and electrical impedance variations that can distinguish nanosized, semi-transparent, structured coatings involving two materials with relatively similar electrical properties. We map heterogeneous interfaces corresponding to an indium tin oxide layer exposed by holes with diameters as small as ~550 nm in a titanium (dioxide) over-layer deposited on a glass support. We show that electrical modulation during the phase imaging of a macro-electrode is decisive for retrieving electrical impedance distributions with submicron spatial resolution and beyond the limitations of electrode-based technologies (surface or scanning technologies). The findings, which are substantiated by a theoretical model that fits the experimental data very well enable achieving electro-optical maps with high spatial and temporal resolutions. The virtues and limitations of the novel optoelectrochemical method that provides grounds for a wider range of electrically modulated optical methods for measuring the electric field locally are critically discussed.
通过具有高信噪比的无损检测快速获取纳米级电阻抗图谱是一项尚未满足的需求，这可能会影响从生物医学到能量转换的各种应用。在本研究中，我们开发了一种多模态功能成像仪器，其特点是具有阻抗映射和相位定量的双重能力、高空间分辨率和低时间噪声。为实现这一目标，我们改进了一种定量相位成像系统，称为落射放大图像空间光谱显微镜与电驱动相结合，以提供光程和电阻抗的互补图谱。我们通过光程差和电阻抗变化的高分辨率图谱展示了我们的系统，这些图谱能够区分涉及两种具有相对相似电学性质的材料的纳米级、半透明、结构化涂层。我们绘制了与铟锡氧化物层对应的异质界面，该层在沉积在玻璃载体上的钛（二氧化钛）覆盖层中被直径小至约550 nm的孔暴露。我们表明，在宏观电极的相位成像期间进行电调制对于以亚微米空间分辨率检索电阻抗分布以及超越基于电极的技术（表面或扫描技术）的局限性至关重要。这些发现得到了一个与实验数据拟合得非常好的理论模型的证实，能够实现具有高空间和时间分辨率的电光图谱。本文对这种新型光电化学方法的优点和局限性进行了批判性讨论，为更广泛的用于局部测量电场的电调制光学方法提供了依据。
