Optical field terahertz amplitude modulation by graphene nanoribbons

In this study, first-principles time-dependent density functional theory calculations were used to demonstrate the possibility to modulate the amplitude of the optical electric field (E-field) near a semiconducting graphene nanoribbon. A significant enhancement of the optical E-field was observed 3.34 Å above the graphene nanoribbon sheet, with an amplitude modulation of approximately 100 fs, which corresponds to a frequency of 10 THz. In general, a six-fold E-field enhancement could be obtained, which means that the power of the obtained THz is about 36 times that of incident UV light. We suggest the use of semiconducting graphene nanoribbons for converting visible and UV light into a THz signal.
HZ and XLC acknowledge financial support from the National Natural Science Foundation of China (Grant No. 11474207 and Grant No. 11374217). YM acknowledges the fund from MEXT, Grant-in-Aid for Scientific Research on Innovative Areas “Science of Atomic Layers (SATL)”, Japan, and the support from Research organization of Information Science and Technology (RIST) at Tokyo. AR acknowledges financial support from the European Research Council Advanced Grant DYNamo (ERC-2010-AdG-267374), Spanish Grant (FIS2013-46159-C3-1-P), Grupos Consolidados UPV/EHU del Gobierno Vasco (IT578-13) and COST Actions CM1204 (XLIC) and MP1306 (EUSpec).