title: Imaging electric field dynamics with graphene optoelectronics.
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.
authors.affiliation: Department of Physics, University of California Berkeley, Berkeley, California 94720, USA.|Kavli Energy NanoSciences Institute at the University of California Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: Jason
authors.initials: J
authors.lastname: Horng
authors.affiliation: Department of Physics, University of California Berkeley, Berkeley, California 94720, USA.|Kavli Energy NanoSciences Institute at the University of California Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: Halleh B
authors.initials: HB
authors.lastname: Balch
authors.affiliation: Department of Chemistry, Stanford University Stanford, California 94305, USA.
authors.forename: Allister F
authors.initials: AF
authors.lastname: McGuire
authors.affiliation: Department of Physics, University of California Berkeley, Berkeley, California 94720, USA.
authors.forename: Hsin-Zon
authors.initials: HZ
authors.lastname: Tsai
authors.affiliation: Department of Physics, University of California Berkeley, Berkeley, California 94720, USA.
authors.forename: Patrick R
authors.initials: PR
authors.lastname: Forrester
authors.affiliation: Department of Physics, University of California Berkeley, Berkeley, California 94720, USA.|Kavli Energy NanoSciences Institute at the University of California Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.|Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: Michael F
authors.initials: MF
authors.lastname: Crommie
authors.affiliation: Department of Chemistry, Stanford University Stanford, California 94305, USA.
authors.forename: Bianxiao
authors.initials: B
authors.lastname: Cui
authors.affiliation: Department of Physics, University of California Berkeley, Berkeley, California 94720, USA.|Kavli Energy NanoSciences Institute at the University of California Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.|Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: Feng
authors.initials: F
authors.lastname: Wang