Fano-Resonant Hybrid Metamaterial for Enhanced Nonlinear Tunability and Hysteresis Behavior

Artificial resonant metamaterial with subwavelength localized filed is promising for advanced nonlinear photonic applications.In this article,we demonstrate enhanced nonlinear frequency-agile response and hysteresis tunability in a Fano-resonant hybrid metamaterial.A ceramic cuboid is electromagnetically coupled with metal cut-wire structure to excite the high-Q Fano-resonant mode in the dielectric/metal hybrid metamaterial.It is found that the significant nonlinear response of the ceramic cuboid can be employed for realization of tunable metamaterials by exciting its magnetic mode,and the trapped mode with an asymmetric Fano-like resonance is beneficial to achieve notable nonlinear modulation on the scattering spectrum.The nonlinear tunability of both the ceramic structure and the ceramic/metal hybrid metamaterial is promising to extend the operation band of metamaterials,providing possibility in practical applications with enhanced light-matter interactions.

Active control of EIT-like response in a symmetry-broken metasurface with orthogonal electric dipolar resonators

The active control of electromagnetic response in metamaterial and mutual coupling between resonant building blocks is of fundamental importance in realizing high-quality metamaterials. In this work, we propose and experimentally demonstrate the tunabilities of symmetry-broken metasurfaces made of orthogonal electric dipolar resonators. The metasurface with vertical and horizontal wires is integrated with a PIN diode for active control.It is found that the electromagnetically induced transparency(EIT)-like spectrum appears due to the destructive or constructive interferences between the two electric dipolar modes when the structural symmetry broken is introduced to the metasurface. Different from previous works on the EIT-like effect, there is only electric dipole response in our metasuface. The microscopic response of the metasurface is numerically calculated to illustrate the mode coupling between the orthogonal electric dipolar resonators. By applying temporal coupled-mode theory,the interaction between the electromagnetic wave and the symmetry-broken metasurface is described, and the characteristic parameters of the resonator system, which determine the electromagnetic response of the metasurface, are acquired.

Subwavelength optical localization with toroidal excitations in plasmonic and Mie metamaterials

Since the performance of electronic circuits is becoming rather limited in face of intensively increasing of amount of information and related operations,alloptical processing offers a promising strategy for future information system.It would benefit a great deal if the all-optical processing could be implemented within the developed electronic chips of nanoscale structures.In that it is highly desirable to break the diffraction limit of light for achieving effective light manipulations with deep subwavelength structures compatible with the state-of-the-art nanofabrication processes.It is of fundamental importance to get subwavelength optical localization,that is,squeeze light wave into subwavelength space for achieving freely manipulating of light fields.This review summarizes the development in realizing subwavelength optical localization by exciting toroidal mode in photonic metamaterials.The toroidal excitations in plasmonic metamaterials and Mie resonant metamaterials,in 3D structures and planar metamaterials,with single or few layers in spectral regime from microwave to optical frequencies are surveyed.Based on the discussion on the configurations of toroidal excitations,the recent development on toroidalrelated optical scattering control actively manipulates the toroidal excitations,and promising applications are further investigated and highlighted.