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We theoretically study resonance responses of flat surfaces and sharp edges of the nanostructures that support excitations of phonon-polaritons in mid-infrared range. We focus on two materials: silicon carbide that has a nearly isotropic permittivity and hexagonal boron nitride that has a strong anisotropy and spectral band with hyperbolic dispersion. We aim to predict scattering-type near-field optical microscope (s-SNOM) response and develop a modeling approach that adequately describes the resonant behavior of the nanostructure with phonon-polaritons. The previously employed technique assumes dipole scattering from the tip and allows calculating s-SNOM signal in different demodulation orders by modeling full structure, any tip positions, and vertical scans, which works well for the structures with only one hot spot, e.g. flat surfaces. In the structures of complex shapes, hot-spot places are unknown, and analysis of light absorption in the whole apex is the best way to account for all hot spots and field enhancement. We show that calculation of demodulation orders of light absorption in the tip is an alternative way to predict s-SNOM signal, and it is preferred for the structures of complex shapes with strong resonances, where dipole approximation of the tip is not valid.
Scattering-type scanning near-field optical microscopy (s-SNOM) is instrumental in exploring polaritonic behaviors of two-dimensional (2D) materials at the nanoscale. A sharp s-SNOM tip couples momenta into 2D materials through phase matching to exci
We present combined experimental and numerical work on light-matter interactions at nanometer length scales. We report novel numerical simulations of near-field infrared nanospectroscopy that consider, for the first time, detailed tip geometry and ha
Optical spin angular momenta in a confined electromagnetic field exhibit remarkable difference with their free space counterparts, in particular, the optical transverse spin that is locked with the energy propagating direction lays the foundation for
A signature of the scattering between microcavity polaritons and longitudinal optical phonons has been observed in the electroluminescence spectrum of an intersubband device operating in the light-matter strong coupling regime. By electrical pumping
Imaging dynamical processes at interfaces and on the nanoscale is of great importance throughout science and technology. While light-optical imaging techniques often cannot provide the necessary spatial resolution, electron-optical techniques damage