Imaging electric field dynamics with graphene optoelectronics

TL;DR

This paper introduces a novel, label-free graphene-based imaging method capable of real-time, high-sensitivity visualization of electric field distributions with high spatial and temporal resolution, applicable in bioelectric and microfluidic contexts.

Contribution

The authors develop a new graphene optoelectronic technique combining gate-variable optical transitions with a waveguide platform for sensitive electric field imaging under ambient conditions.

Findings

Voltage sensitivity of a few microvolts achieved

Spatial resolution of tens of micrometres demonstrated

Frequency response over tens of kilohertz confirmed

Abstract

The use of electric fields for signalling and control in liquids is widespread, spanning bioelectric activity in cells to electrical manipulation of microstructures in lab-on-a-chip devices. However, an appropriate tool to resolve the spatio-temporal distribution of electric fields over a large dynamic range has yet to be developed. Here we present a label-free method to image local electric fields in real time and under ambient conditions. Our technique combines the unique gate-variable optical transitions of graphene with a critically coupled planar waveguide platform that enables highly sensitive detection of local electric fields with a voltage sensitivity of a few microvolts, a spatial resolution of tens of micrometres and a frequency response over tens of kilohertz. Our imaging platform enables parallel detection of electric fields over a large field of view and can be tailored to broad applications spanning lab-on-a-chip device engineering to analysis of bioelectric phenomena.