Goos-Hänchen Shift and Even-Odd Peak Oscillations in Edge-Reflections of Surface Polaritons in Atomically Thin Crystals.
Two-dimensional surface polaritons (2DSPs), such as graphene plasmons, exhibit various unusual properties, including electrical tunability and strong spatial confinement with high Q-factor, which can enable tunable photonic devices for deep subwavelength light manipulations. Reflection of plasmons at the graphene's edge plays a critical role in the manipulation of 2DSP and enables their direct visualization in near-field infrared microscopy. However, a quantitative understanding of the edge-reflections, including reflection phases and diffraction effects, has remained elusive. Here, we show theoretically and experimentally that edge-reflection of 2DSP exhibits unusual behaviors due to the presence of the evanescent waves, including an anomalous Goos-Hänchen phase shift as in total internal reflections and an unexpected even-odd peak amplitude oscillation from the wave diffraction at the edge. Our theory is not only valid for plasmons in graphene but also for other 2D polaritons, such as phonon polaritons in ultrathin boron nitride flakes and exciton polariton in two-dimensional semiconductors.
Department of Physics, University of California at Berkeley , Berkeley, California 94720, United States.
Ji-Hun
0000-0002-2201-1689
JH
Kang
Department of Physics, University of California at Berkeley , Berkeley, California 94720, United States.|Materials Science Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
Sheng
S
Wang
Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University , Shanghai 200240, China.|Collaborative Innovation Center of Advanced Microstructures , Nanjing 210093, China.
Zhiwen
Z
Shi
Department of Physics, University of California at Berkeley , Berkeley, California 94720, United States.|Department of Physics, Harbin Institute of Technology , Harbin 150001, China.
Wenyu
W
Zhao
Materials Science Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.|Department of Electrical Engineering and Computer Science, University of California at Berkeley , Berkeley, California 94720, United States.|Kavli Energy NanoSciences Institute at the University of California, Berkeley and the Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
Eli
E
Yablonovitch
Department of Physics, University of California at Berkeley , Berkeley, California 94720, United States.|Materials Science Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.|Kavli Energy NanoSciences Institute at the University of California, Berkeley and the Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
Feng
F
Wang
Goos-Hänchen shift; Graphene; Near-field infrared microscopy; Plasmonics; Surface polariton; van der Waals materials