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| VOLUME 110 (2019) | ISSUE 1 | PAGE 21 |
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Revealing low-radiative modes of nanoresonators with internal raman scattering
K. V. Baryshnikova+, K. Frizyuk+, G. Zograf +, S. Makarov+, M. A. Baranov+, D. Zuev+, V. A. Milichko+, I. Mukhin+*, M. Petrov+×, A. B. Evlyukhin+°
+Department of Nanophotonics and Metamaterials, ITMO University, 197101 St. Petersburg, Russia *Laboratory of Renewable Energy Sources, St.-Petersburg Academic University, 195220 St. Petersburg, Russia ×Department of Physics and Mathematics, University of Eastern Finland, 80101 Joensuu, Finland °Institute of Quantum Optics, Leibniz Universitét Hannover, 30167 Hannover, Germany
Abstract
Revealing hidden non-radiative (dark) modes of resonant nanostructures using optical methods such as dark-field spectroscopy often becomes a sophisticated problem due to a weak coupling of these modes with a far-field radiation, whereas methods of dark-modes spectroscopy, e.g., cathodoluminescence or elastic energy losses, are not always convenient in use. Here, we suggest an approach for experimental determining the mode structure of a nanoresonator basing on utilizing intrinsic incoherent Raman scattering. We theoretically predict the efficiency of this approach and realize it experimentally for silicon nanoparticle resonators possessing strong Raman line at 520 cm-1. With this method we studied a silicon nanoparticle placed on a gold substrate and revealed the spectral position of a low-radiative magnetic quadrupole mode which is hardly observable with common dark-field optical spectroscopy. |