2021/04/08 by Xia Zhang, Zhang, Xia, A. Louise Bradley +1
Engineering · Materials Science · #FOS: Physical sciences #Metamaterials and Metasurfaces Applications #Optics (physics.optics) #Photonic and Optical Devices #Plasmonic and Surface Plasmon Research
paper · pdf · doi:10.48550/arxiv.2104.03463
openalex publication_date 2021/04/08 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
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 \rm Q ∼ 106, accompanying an ultra-small effective mode volume, \rm Vm ∼ 10-2 (λ/n)3 are achieved resulting in a Purcell factor of \rm 106 (λ/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.