Non-plasmonic nanoantennas for field-enhanced spectroscopy beyond the plasmonic limit

Dielectric nanostructures with a high refractive index and a low optical loss have recently attracted considerable attention as an alternative to plasmonic nanostructures. The electromagnetic multipoles excited in the high-index dielectric nanostructures enable the manipulation of light beyond the diffraction limit and offer high electromagnetic field enhancement comparable to that exhibited by the plasmonic nanostructures. Here, we demonstrate all-dielectric field enhanced spectroscopy using high-index dielectric nanoantenna and metasurface, enabling us to perform Raman and Infrared spectroscopies with single molecule detection sensitivity.