Far-Field Spectroscopy and Near-Field Optical Imaging of Coupled Plasmon–Phonon Polaritons in 2D van der Waals Heterostructures

X. Yang, F. Zhai, H. Hu, D. Hu, R. Liu, S. Zhang, M. Sun, Z. Sun, J.Chen and Q. Dai

Advanced Materials 28, Issue 15, pp. 2931–2938 (2016)
A new hybridized plasmon–phonon polariton mode in graphene/h-BN van der Waals heterostructures is presented, featuring the ultrahigh field confinement characteristic of the graphene plasmon and the long lifetime property of the h-BN transverse optical phonon. This enables an ultralong hybrid plasmon lifetime of up to 1.6 ps (with ultrahigh mode confinement up to >l02/7000 and ultrasmall group velocity down to 0.001c, where c is the speed of light in vacuum), superior to any localized plasmon ever demonstrated.