PhD Mid-term Seminar Series: Nanoscale guiding of infrared light with hyperbolic volume and Surface polaritons in van der Waals material ribbons
CIC nanoGUNE Seminars
- Speaker
-
Irene Dolado, Nanooptics Group
- When
-
2020/02/24
12:00 - Place
- nanoGUNE seminar room, Tolosa Hiribidea 76, Donostia - San Sebastian
- Add to calendar
- iCal
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**Nanoscale guiding of infrared light with hyperbolic volume and Surface
polaritons in van der Waals material ribbons**
Van der Waals (vdW) materials host a variety of polaritons, which make them an
emerging material platform for manipulating light at the nanoscale. Due to the
layered structure of vdW materials, the polaritons can exhibit a hyperbolic
dispersion and propagate as nanoscaleâ€confined volume modes in thin flakes.
On the other hand, surfaceâ€confined modes can be found at the flake edges.
Surprisingly, the guiding of these modes in ribbons—representing typical
linear waveguide structures—is widely unexplored. Here, a detailed study of
hyperbolic phonon polaritons propagating in hexagonal boron nitride ribbons is
reported. Employing infrared nanoimaging, a variety of modes are observed.
Particularly, the fundamental volume waveguide mode that exhibits a cutoff
width is identified, which, interestingly, can be lowered by reducing the
waveguide thickness. Further, hybridization of the surface modes and their
evolution with varying frequency and waveguide width are observed. Most
importantly, it is demonstrated that the symmetrically hybridized surface mode
does not exhibit a cutoff width, and thus enables linear waveguiding of the
polaritons in arbitrarily narrow ribbons. The experimental data, supported by
simulations, establish a solid basis for the understanding of hyperbolic
polaritons in linear waveguides, which is of critical importance for their
application in future photonic devices.