Femtosecond photo-switching of interface polaritons in black phosphorus heterostructures

Nature Nanotechnology 12, 207 (2017). doi:10.1038/nnano.2016.261 Authors: Markus A. Huber, Fabian Mooshammer, Markus Plankl, Leonardo Viti, Fabian Sandner, Lukas Z. Kastner, Tobias Frank, Jaroslav Fabian, Miriam S. Vitiello, Tyler L. Cocker & Rupert Huber The possibility of hybridizing collective electronic motion with mid-infrared light to form surface polaritons has made van der Waals layered materials a versatile platform for extreme light confinement and tailored nanophotonics. Graphene and its heterostructures have attracted particular attention because the absence of an energy gap allows plasmon polaritons to be tuned continuously. Here, we introduce black phosphorus as a promising new material in surface polaritonics that features key advantages for ultrafast switching. Unlike graphene, black phosphorus is a van der Waals bonded semiconductor, which enables high-contrast interband excitation of electron–hole pairs by ultrashort near-infrared pulses. Here, we design a SiO2/black phosphorus/SiO2 heterostructure in which the surface phonon modes of the SiO2 layers hybridize with surface plasmon modes in black phosphorus that can be activated by photo-induced interband excitation. Within the Reststrahlen band of SiO2, the hybrid interface polariton assumes surface-phonon-like properties, with a well-defined frequency and momentum and excellent coherence. During the lifetime of the photogenerated electron–hole plasma, coherent hybrid polariton waves can be l...
Source: Nature Nanotechnology - Category: Nanotechnology Authors: Tags: Letter Source Type: research