We investigate plasmon resonances in graphene with periodic carrier density modulation. The period is 8 um, and each period consists of 1.7- and 6.3-um-wide ribbons with different density. Using terahertz spectroscopy, we show two plasmon modes with their electric field mostly localized in the 1.7- or 6.3-um-wide ribbon arrays. We also show that plasmons are excited only in one of the micro-ribbon arrays when the Fermi energy of the other micro-ribbon array is set close to the charge neutrality point. These results indicate that plasmons can be confined by the carrier density modulation.
@article{arxiv.1812.01266,
title = {Plasmon Confinement by Carrier Density Modulation in Graphene},
author = {Ngoc Han Tu and Makoto Takamura and Yui Ogawa and Satoru Suzuki and Norio Kumada},
journal= {arXiv preprint arXiv:1812.01266},
year = {2018}
}