▎ 摘　　要

High-resolution electron energy loss spectroscopy has been used to investigate the effects of air exposure on the plasmon modes of a graphene-Ru contact. We found that graphene plasmons are quenched after the exposure of the sample to ambient air humidity. This finding represents a severe hurdle for THz plasmonic graphene-based devices, in which graphene-metal contacts are inevitable components. (C) 2013 AIP Publishing LLC.