Measuring the Complex Optical Conductivity of Graphene by Fabry-Pérot Reflectance Spectroscopy.
We have experimentally studied the dispersion of optical conductivity in few-layer graphene through reflection spectroscopy at visible wavelengths. A laser scanning microscope (LSM) with a supercontinuum laser source measured the frequency dependence of the reflectance of exfoliated graphene flakes, including monolayer, bilayer and trilayer graphene, loaded on a Si/SiO2Fabry-Pérot resonator in the 545-700 nm range. The complex refractive index of few-layer graphene, n - ik, was extracted from the reflectance contrast to the bare substrate. It was found that each few-layer graphene possesses a unique dispersionless optical index. This feature indicates that the optical conductivity does not simply scale with the number of layers, and that inter-layer electrodynamics are significant at visible energies.
Center for Nanophysics and Advanced Materials, Department of Physics, University of Maryland, College Park, MD, 20742-4111, USA.
Behnood G
BG
Ghamsari
Center for Nanophysics and Advanced Materials, Department of Physics, University of Maryland, College Park, MD, 20742-4111, USA.
Jacob
J
Tosado
Center for Nanophysics and Advanced Materials, Department of Physics, University of Maryland, College Park, MD, 20742-4111, USA.
Mahito
M
Yamamoto
Center for Nanophysics and Advanced Materials, Department of Physics, University of Maryland, College Park, MD, 20742-4111, USA.
Michael S
MS
Fuhrer
Center for Nanophysics and Advanced Materials, Department of Physics, University of Maryland, College Park, MD, 20742-4111, USA.
Steven M
SM
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