Revealing Nanoscale Confinement Effects on Hyperbolic Phonon Polaritons with an Electron Beam
Abstract
Hyperbolic phonon polaritons (HPhPs) in hexagonal boron nitride (hBN) enable the direct manipulation of mid‐infrared light at nanometer scales, many orders of magnitude below the free‐space light wavelength. High‐resolution monochromated electron energy‐loss spectroscopy (EELS) facilitates measurement of excitations with energies extending into the mid‐infrared while maintaining nanoscale spatial resolution, making it ideal for detecting HPhPs. The electron beam is a precise source and probe of HPhPs, which allows the observation of nanoscale confinement in HPhP structures and directly extract hBN polariton dispersions for both modes in the bulk of the flake and modes along the edge. The measurements reveal technologically important nontrivial phenomena, such as localized polaritons induced by environmental heterogeneity, enhanced and suppressed excitation due to 2D interference, and strong modification of high‐momenta excitations such as edge‐confined polaritons by nanoscale heterogeneity on edge boundaries. The work opens exciting prospects for the design of real‐world optical mid‐infrared devices based on hyperbolic polaritons.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Aug 28, 2021
- Source ID
- 10.1002/smll.202103404
Entities
People
- Andrea Konečná
- F. Javier García de Abajo
- James H Edgar
- Jiahan Li
- Jordan A Hachtel
Organizations
- Barcelona Institute for Science and Technology
- Catalan Institution for Research and Advanced Studies
- Central European Institute of Technology
- European Commission
- European Research Council
- Kansas State University
- Oak Ridge National Laboratory
- Office of Naval Research