We demonstrate terahertz (THz) imaging and spectroscopy of a 15x15-mm^2 single-layer graphene film on Si using broadband THz pulses. The THz images clearly map out the THz carrier dynamics of the graphene-on-Si sample, allowing us to measure sheet conductivity with sub-mm resolution without fabricating electrodes. The THz carrier dynamics are dominated by intraband transitions and the THz-induced electron motion is characterized by a flat spectral response. A theoretical analysis based on the Fresnel coefficients for a metallic thin film shows that the local sheet conductivity varies across the sample from {\sigma}s = 1.7x10^-3 to 2.4x10^-3 {\Omega}^-1 (sheet resistance, {\rho}s = 420 - 590 {\Omega}/sq).
@article{arxiv.1101.1338,
title = {Terahertz imaging and spectroscopy of large-area single-layer graphene},
author = {J. L. Tomaino and A. D. Jameson and J. W. Kevek and M. J. Paul and A. M. van der Zande and R. A. Barton and P. L. McEuen and E. D. Minot and Yun-Shik Lee},
journal= {arXiv preprint arXiv:1101.1338},
year = {2011}
}