Strong coupling between excitons and chiral quasibound states in the continuum of the bulk WS metasurface.

In the fields of optics and photonics, the topic of light-matter interactions, particularly strong coupling effects, is a developing area of research. Exciton polariton, a hybridized state brought about by strong coupling, is a hot topic, especially from the standpoint of chiral optics. Under the incidence of right circularly polarized light and left circularly polarized (RCP and LCP) light, we investigate the strong coupling between excitons and quasibound states in the continuum (Q-BICs) resonance in a bulk WS metasurface.

Ultrasensitive optical reflectivity in annular nanohole array on Photonic crystal slab based on bound states in the continuum.

We investigate optical bound states in the continuum (BICs) supported by a photonic crystal (PhC) slab penetrated with periodic annular holes theoretically. Ultrahigh-quality factor (Q-factor) resonances associated with BICs are obtained with a Q-factor more than 10. The BICs can be seen at nonzero incident angles by tuning the lattice constant, layer thickness, inner pillar radius and the refractive index of the surrounding medium, and figure of merit (FOM) at the BICs can reach infinite theoretically.

Effects of symmetry breaking on plasmon resonance in a noncoaxial nanotube and nanotube dimer.

The effects of symmetry breaking on plasmonic properties of one nanotube and three types of nanotube dimers are numerically investigated. It is found that increasing the coaxial offset can result in redshifting of the transmission spectra and the existence of more peaks in the nanoegglike structures, while the nanocuplike structures present the opposite and more complex behaviors. We also study the combined effects of coaxial offset and gap size.

Tunable optical transmission through gold slit arrays with Z-shaped channels.

The transmission of a normally incident wave through an array of subwavelength gold film with Z-shaped slits has been explored by using the finite-difference time-domain method. The results show that the transmission of a thinner metal film perforated with a Z-shaped slit array behaves nearly the same as that of a thicker metal film perforated with straight slit array with the same central slit length, which is useful for the miniaturization of the optical device. It is also presented that the transmission of a Z-shaped slit array sensitively depends on the slit geometrical parameters.

Tunable phase resonances in a compound metallic grating with perpendicular bumps and cuts.

We propose a compound metallic grating with perpendicular bumps in each slit and investigate its transmission property theoretically. As the bumps are set symmetrically in the slits, the waveguide resonant peaks for the even (odd) modes exhibit a red-shift (blue-shift) compared with the resonant peaks of grating composed of bare slit. As the bumps are set asymmetrically, we show that the dips in transmission spectrum can be tuned by shifting the position and changing the size of bumps in the slit.