%APolonschii, Cristina%AGheorghiu, Mihaela%ADavid, Sorin%AGáspár, Szilveszter%AMelinte, Sorin%AMajeed, Hassaan%AKandel, Mikhail%APopescu, Gabriel%AGheorghiu, Eugen%Anull Ed.%BJournal Name: Light: Science & Applications; Journal Volume: 10; Journal Issue: 1 %D2021%I %JJournal Name: Light: Science & Applications; Journal Volume: 10; Journal Issue: 1 %K %MOSTI ID: 10289847 %PMedium: X %THigh-resolution impedance mapping using electrically activated quantitative phase imaging %XAbstract 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. %0Journal Article