BOUNDEDNESS AND EXPONENTIAL STABILITY FOR NONAUTONOMOUS FCNNs WITH REACTION-DIFFUSION TERMS AND TINE-VARYING DELAYS

In this paper, a class of nonautonomous fuzzy cellular neural networks (FCNNs) with reaction-diffusion terms and time-varying delays are investigated. By applying the inequality analysis technique, introducing ingeniously many real parameters and constructing new auxiliary functions, a series of new and useful criteria on the boundedness and globally exponential stability of solutions are established. The results obtained in this paper extend and improve the corresponding results given in previous works. Finally, two examples are given to verify the effectiveness of the obtained results. </jats:p

Structured vortices generated by metasurface holography

Highly customized and miniaturized structured light is expected in many application fields. A kind of structured vortex generators is proposed based on a metasurface consisting of rectangular nanoholes etched in a silver film, and the generated vortices with the same or different topological charges are distributed along the radial direction. The geometric metasurface is completed with the help of optical holography technology, and the structured vortex generator possesses high working efficiency and large information capacity. The proposed vortex generators work under circularly polarized light illumination, and the reproduced vortices of multiplexing vortex generator depend on the handedness of the circularly polarized light. This work paves a way to generate new structured light fields. The radially distributed vortices may be utilized to simultaneously screen or separate microparticles. The compact design of the structured vortex generator and the convenient switch of different structured vortices will be a benefit to expand the applications of structured vortex fields.</jats:p

Metasurface circular polarizer based on rotational symmetric nanoholes

Abstract A circular polarizer is proposed based on a single layered metasurface. This metasurface circular polarizer is composed of L-shaped nanoholes etched on the silver film. The L-shaped nanoholes are rotational symmetric, and the special symmetric structure determines the polarization selection transmission of the metasurface. The theoretical analysis elaborates the design process of the metasurface circular polarizer. The proposed metasurface circular polarizers have good polarization selective transmittance, and more interestingly, they take on the opposite circular dichroism at different wavebands. The numerical simulations and experiment measurement confirm the circular dichroism of the proposed circular polarizers. The compact design, ultrathin thickness and available performance can expand the applications of the metasurface circular polarizers in the integrated optics.</jats:p