Magnetic and electric toroidal dipoles possess interesting properties differing from traditional electric and magnetic dipoles. In order to generate both the magnetic and electric toroidal dipoles simultaneously in one single structure, a permittivity-asymmetric dielectric metasurface is proposed, which is composed of clusters of four high-index dielectric nano-disks with asymmetric permittivity distribution. These two types of toroidal dipole responses can be separately observed at different spectral positions. This study reveals that symmetry-breaking in a broad sense is crucial for exciting toroidal responses, and the proposed metasurface points to a unique routine of exciting and enhancing the toroidal responses, which may be used to realize efficient light–matter interaction in the area of meta-optics.

We propose a dielectric metasurface constructed by quadrumer silicon nano-disks with crossed slots in the middle. This metasurface can support the excitation of bound states in the continuum which are...

A cylindrical chiral-graphene-dielectric waveguide structure is proposed. Correspondingly, characteristics of surface plasmonic mode are theoretically investigated, including dispersion relation, intensity, phase and polarization distribution. The proposed waveguide can only support the vortex modes with the hybrid polarization distribution, which originates from the spin-momentum locking of evanescent electromagnetic waves. The circular birefringence of chiral materials releases the degeneracy between same-order vortex modes. In addition, the number of modes can be controlled by changing the radius of the dielectric nanowire and the Fermi level of graphene. The effective index and corresponding propagation length of the mode are sensitive to the chiral parameter. We believe the proposed waveguide can find some potential applications in multiplex communication, chiral sensing and the fabrication of tunable nano-photonic devices.

The propagating behavior of surface plasmons in chiral media is different from that in achiral media. By comparing the propagation behavior of SPPs, the chirality of the environment can be...

We propose a design of anti-resonant fiber by introducing the chiral material into the inner regions of the six germanium-doped silica glass cladding tubes, which can support the operation of single-mode single left-handed circular polarization in the communication band from 1.540 to 1.605 μm. Especially, the loss reaches a minimum value of 0.009 dB/m at 1.550 μm. The sign of chiral parameter can control the handedness of polarization in the operation of single-mode single-circular polarization. In addition, the anti-resonant fiber possesses a good bending resistance performance. The minimum bending radius of the anti-resonant fiber is 10 cm to maintain the single-mode single left-handed circular polarization for 1.550 μm. We believe the novel anti-resonant fiber can find applications in optical communication, polarization imagining and chiral sensing.