[18a-211B-1~7] 4.1 Plasmonics and Nanophotonics

▲ [18a-211B-5] Plasmon activated forbidden phonon modes in defect-free graphene by tip-enhanced nano-confined light

〇(PC)Maria Balois¹, Norihiko Hayazawa^1,2,3,4, Satoshi Yasuda⁵, Katsuyoshi Ikeda⁶, Bo Yang², Emiko Kazuma², Yasayuki Yokota², Yousoo Kim², Takuo Tanaka^1,4,7 (1.RIKEN - RAP, 2.RIKEN - SISL, 3.NIP - UP Diliman, 4.Tokyo Inst. of Tech., 5.JAEA, 6.Nagoya Inst. of Tech, 7.RIKEN - Mets Lab)

Keywords:tip-enhanced Raman spectroscopy, graphene

High photon confinement and the field gradient effect can alter selection rules in Raman spectroscopy. We report the first observation of the forbidden combination Raman modes in defect-free monolayer graphene on an Au(111) substrate whose Raman peak lies at 2919.1 cm^-1.The occurrence of the forbidden combination Raman modes alongside the D and D’ modes is due to the nano confined light generated at the tip apex that, in turn, generates a strong field gradient.