University of Minnesota
School of Physics & Astronomy

Physics and Astronomy Calendar

Tuesday, March 27th 2018
Speaker: Michael Fogler, University of California, San Diego
Subject: Hyperbolic waves in Nature: from nano to Ter(r)a

Waves with a hyperbolic dispersion relation are exotic yet surprisingly widespread phenomena that occur in anisotropic media with internal resonances. Such media have been investigated in numerous fields, ranging from condensed matter physics to plasma physics to optics to fluid dynamics and geophysics. Hyperbolic waves can be found in magnetic materials, in both usual and topological insulators, in superconductors, as well as in our oceans, beaches, atmosphere, and space. The characteristic lengths and frequencies of such waves vary vastly, from atomic to cosmic. However, they all exhibit certain common attributes, such as strict directionality, diverging density of states, and anomalous reflection. This talk will contain a primer on hyperbolic materials, a recipe for the death ray, and a report on our nano-optics studies of hyperbolic phonon-polaritons in new quasi-2D materials such as graphene and hexagonal boron nitride.

References:

1. L. V. Brown et al, “Nanoscale Mapping and Spectroscopy of Nonradiative Hyperbolic Modes in Hexagonal Boron Nitride Nanostructures,” Nano Lett. 18, 1628 (2018).
2. A. J. Giles et al., "Imaging of Anomalous Internal Reflections of Hyperbolic Phonon-Polaritons in Hexagonal Boron Nitride," Nano Lett. 16, 3858 (2016).
3. S. Dai et al., “Subdiffractional focusing and guiding of polaritonic rays in a natural hyperbolic material,” Nature Comms 6, 6963 (2015).
4. S. Dai et al., “Tunable Phonon Polaritons in Atomically Thin van der Waals Crystals of Boron Nitride”, Science 343, 1125 (2014).

Faculty Host: Boris Shklovskii

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