title: Subwavelength Terahertz Imaging of Graphene Photoconductivity.
abstract: Using a spatially structured, optical pump pulse with a terahertz (THz) probe pulse, we are able to determine spatial variations of the ultrafast THz photoconductivity with subwavelength resolution (75 μm ≈ λ/5 at 0.8 THz) in a planar graphene sample. We compare our results to Raman spectroscopy and correlate the existence of the spatial inhomogeneities between the two measurements. We find a strong correlation with inhomogeneity in electron density. This demonstrates the importance of eliminating inhomogeneities in doping density during CVD growth and fabrication for photoconductive devices.
authors.affiliation: Physics Building, Stocker Road, University of Exeter , Exeter, Devon, United Kingdom , EX4 4QL.
authors.forename: Samuel M
authors.initials: SM
authors.lastname: Hornett
authors.affiliation: Physics Building, Stocker Road, University of Exeter , Exeter, Devon, United Kingdom , EX4 4QL.
authors.forename: Rayko I
authors.initials: RI
authors.lastname: Stantchev
authors.affiliation: Physics Building, Stocker Road, University of Exeter , Exeter, Devon, United Kingdom , EX4 4QL.
authors.forename: Martha Z
authors.initials: MZ
authors.lastname: Vardaki
authors.affiliation: Physics Building, Stocker Road, University of Exeter , Exeter, Devon, United Kingdom , EX4 4QL.
authors.forename: Chris
authors.initials: C
authors.lastname: Beckerleg
authors.affiliation: Physics Building, Stocker Road, University of Exeter , Exeter, Devon, United Kingdom , EX4 4QL.
authors.forename: Euan
authors.initials: E
authors.lastname: Hendry
keywords: Graphene; imaging; terahertz; ultrafast