Moreover, SSAIL does not require special additives in the polymer matrix, and standard commercial material (available on the market) can be used as a circuit carrier. Compared with other plating technologies, the main advantage of the SSAIL process is that process is selective, and copper deposition appears only on the laser-modified surface. The new technology offers laser writing speeds of up to 4 m/s, and herewith spatial plating pitch is kept as narrow as 25 µm. SSAIL contains 3 main steps: laser modification of the dielectric surface, chemical activation of the modified areas by dipping into solution and chemical electroless metal deposition of the activated parts. Therefore, the novel selective surface activation by laser (SSAIL) method is used in this work 21, 22, 23, 24. However, none of the mentioned methods can deposit a metal layer on the PTFE substrate with sufficient adhesion to the substrate. Several methods are known that can be applied to fabricate metasurfaces, such as inkjet printing 17, screen printing 18, roll-to-roll printing 19, chemical vapor deposition 20. Remarkably, our design provides an open (cladding-free) waveguide with great potential for designing multi-wavelength biosensors, refractive-index sensors, and filters. The number of Fano resonances and their characteristic frequencies can be simply adjusted by changing the thickness of the substrate. As a result, they interact with plasmonic mode, and multiple Fano resonances appear. By increasing the substrate's thickness, higher waveguide modes are excited. We propose a scheme for multiple Fano resonance observation via interaction of plasmonic mode with dielectric waveguide modes appearing in a mirror-symmetric array of SRRs deposited on low-loss and low-refractive index polytetrafluoroethylene (PTFE) substrate. In this work, we present the first experimental observation of multiple Fano resonances in the terahertz range in HMW system based on an array of mirror-symmetric split-ring resonators 15, 16. In both cases, to achieve multiple resonances, the unit cells of proposed metasurfaces have been rather complicated. Recently in the GHz frequency range, a multiple electromagnetically induced transparency using a double-layered metasurface 13 and ultra-wideband polarization conversion extension using multiple Fano resonances 14 have been demonstrated experimentally. Theoretical considerations have shown that owing to the multimode characteristics of the slab waveguide, HMW design can offer an easy way to realize multiple Fano resonances in simple metal resonators operating in the far infrared and terahertz spectral ranges 10, 11, 12. Hybrid metamaterial waveguide (HMW) structures have been proposed to establish multiple Fano peaks caused by destructive interference of dark quasi-guided and bright plasmon modes. Multiple Fano resonances in metal–insulator-metal waveguide structures with different shapes of cavities 9 have attracted the attention of many researchers due to their outstanding features, including ease of integration and deep subwavelength confinement of light in the visible and near-infrared wavelengths. Multiple Fano resonances are created by introducing new asymmetries into a planar periodic structure 6, collective excitation of a metamolecule lattice consisting of two different metamaterial resonators 7, by coupling between the surface plasmon-polariton mode and multi-order planar waveguide modes 8. While single Fano resonance arises from combining one bright mode and one dark mode, combining a bright mode with several dark modes can result in several Fano resonances. Multispectral Fano resonances are promising in multichannel biochemical sensing 3, multi-band second harmonic generation 4, and multi-band absorbers/emitters 5. Therefore, it is expected that such a metamaterial might find application in developing a variety of sensors 2.īecause of the different application requirements, research interest in the Fano resonance field has spread from a single Fano resonance to multiple Fano resonances. Due to the weak coupling of the dark mode with the external electric fields, the Fano resonance demonstrates a high resonance quality. Typically, the ring is split into two sections of different lengths where the so-called "dark mode" is excited, responsible for the appearance of the Fano resonance 1. In order to obtain it, additional asymmetry is introduced in the SRR. Fano-type resonances are observed in metasurfaces made of split-ring resonators (SRR).
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |