Ultra-Spatiotemporal Light Confinement in Dielectric Nanocavity Metasurfaces

Abstract

Light concentration with strong temporal and spatial confinement is crucial for tailoring light-matter interaction. Electromagnetic cavity modes in photonic and plasmonic resonators provide platforms for optical field localization. Here, we propose a concept of quasi-bound states in the continuum gap cavity and reveal that ultra spatiotemporal confinements in free-space can be realized in a dielectric nanocavity metasurface. By introducing an asymmetric air slot in a nanodisk resonator, an ultra-high quality factor $\mathrm{Q}\sim 10^6$, accompanying an ultra-small effective mode volume, ${\mathrm{V}}_{\mathrm{m}}\sim 10^{-2}$ $(\lambda /n{)}^3$ are achieved resulting in a Purcell factor of $10^6(\lambda /n{)}^{-3}$ in the visible wavelength range. The toroidal dipole drives the electric and magnetic field concentration in the air gap with a generated vortex polarizing electric field. As an alternative to plasmonic and photonic crystal cavities, our study provides a more intriguing platform for engineering light-matter interaction to advance a plethora of fundamental studies and device applications, such as Purcell factor enhancement, room temperature strong coupling and nonlinear nanophotoncis.

6 pages, 4 figures and Supplementary Material

References in corpus (6)

• Strong coupling between surface plasmon polaritons and emitters
• Realizing strong light-matter interactions between single nanoparticle plasmons and molecular excitons at ambient conditions
• Photon-mediated interactions between distant artificial atoms
• Materials Pushing the Application Limits of Wire Grid Polarizers further into the Deep Ultraviolet Spectral Range
• Dielectric Metamaterials with Toroidal Dipolar Response
• Low mode volume slotted photonic crystal single nanobeam cavity

Cited by in corpus (1)

• Optically resonant all-dielectric diabolo nanodisks