The Study on Near-Field Optical Properties of Polaritons in Two-Dimensional Atomic Crystals
September 29th, 2017 JIAHUA DUAN Institute of Physics

In this talk, I will introduce our near-field imaging of polaritons in two-dimensional layered materials. The experimental results can be categorized into two aspects:

1.We study the polaritonic properties in graphene system. We reveal the electronic structure discrepancies and anisotropic plasmon dynamic at different edge terminations (zigzag or armchair). The graphene plasmons provide a robust polaritonic probe to detect the sophisticated sub-band electronic structure at zigzag-edge with nanoscale resolution. Meanwhile, we introduce one new degree of freedom (strain-disorder) to polaritonic field and firstly image the Anderson transition of graphene plasmons in real-space. Compared with propagating plasmons, the Anderson localized one exhibits enhanced light-matter interaction and higher three-dimensional confinement (~107).

2.We realize the nano-infrared imaging of the interference-free hyperbolic phonon polaritons (HPPs) in boron nitride (hBN) and effectively modify their dispersions. Through in-situ mapping the HPPs launched by wrinkles, metal antenna and conventional AFM tip, we demonstrate that natural wrinkles on hBN can serve as a geometrically independent broadband antenna to launch interference-free HPPs with low loss (γ~0.028).

Seminar, September 29, 2017, 12:00. Seminar Room

Hosted by Prof. Frank Koppens