Researchs On The Phase Resonance And Fano Resonance And Related Phenomena In Metal Micro-and Nanostructures

Surface plasmon polaritons (SPPs) present a new pathway for controlling light. The investigation of SPPs has attained many promising new advances, and quickly mutual infiltrate with other fields, several new research branches have appeared. Recently, it’s demonstrated that subradiant, superradiant and Fano interference can exist in the interactive Plasmon systems, and the interactive parameters can be realized by modifying nanostructures’geometry and arrangement. Because of their asymmetric resonance spectra shapes, they may have potential applications in the bio-sensing, metametarials, photoswith and nonlinear optical devices. Based on the completely synthesizing the available research results, this paper concentrates on the light transmission and surface plasmon resonance properties of various sub-wavelength metallic structures, introduces more regulation factors, discovers some new physical phenomena, analysis of the physical mechanism, and discusses the potential applicative value.The research work in this paper mainly includes five parts as follows:1. We study the transmission and surface plasmon properties of double-layer coaxial nanotubes structures. It demonstrate that compared with the single-wall nanotube, a new transmission band appears in the shorter wavelength region. Via investigation of the structural and dielectric parameters effects on the transmission、electric field distribution and energy distribution, we find that the transmission spectra are very sensitive to the variation of the thickness of tube, distance between inner and outer tube and dielectric parameters. Especially the resonance peak on the leftside of band gap is more sensitive. With the analysis of the localized electric distribution properties, we find that the localized plasmon resonance mode originate from the hybridization of multiple multipole plasmon polaritons. In addition, we investigate coaxial gold nanotube array and nanotubes array with point defect, it is demonstrate that the near field optical response, the intensity, position and line width of plasmon resonance peaks can be modified by adjusting the geometric and dielectric parameters, and the introduction of the point defect can remarkably transform the Plasmon resonance properties, many new Plasmon resonance state emerge.2. Via the investigation of the plasmon resonance properties of split coaxial nanotube pairs, it demonstrates that with the increase of the number of splits more and more sharp dips exist. We think that this split behavior comes from the phase-like resonance between adjacent split coaxial tubes. The resonance peaks are sharply relied on modification of the thickness of tube and dielectric parameters. This research can be used to understand the formation of phase resonance in surface plasmon modes. Moreover, we discuss the transmission and plasmon resonance properties of the plan split ring trimer, and find that the transmission properties strongly depend on modification of the distance between the big split ring and small split ring, the spacing between the small split ring dimer and the thickness of big split ring.3. Discuss the transmission properties of a single non-coaxial nanotube and three types of non-coaxial nanotube dimer, mainly investigate the influence of the coaxial offset on the transmission and Plasmon resonance properties. It is shown that with the increase of axial offset, the transmission spectra and more peaks exist in nanoegglike structures, while for the nanocuplike, it presents opposite and more complex behaviors, such as sigmoid spectra shift emerge. We also study the combined effects of axial offset and gap distance. The results show that when increasing the axial offset and decrease the gap distance, nanoegglike structure’s spectra redshift, nanocuplike structure presents opposite behaviors. From the surface charge asymmetry distribution, we can see that dipolar and multiple hybridized modes exist in the cross section of this structure, and the electric field adjacent thinner side sharply enhance. It means that these structures can be used for biosensor and Raman spectrum. Additionly, we study the transmission properties of two types of non-coaxial gold/silicon/gold multiplayer nanotubes dimmer, and discover whatever the offset of the gold core,or the middle silicon layer,both can notably change the transmission spectra and near electric field distributions.4. The transmission and plasmon characteristic of the dark-bright and dark-bright-dark resonators composed of ellipsoid tripod structures are investigated. It is displayed that resonators’structures and spatial arrangement have a great effect on the resonance spectra. In the symmetric structure, only one transparent windows presents, while introducing asymmetry regardless of structural or spatial arrangement, a new transparent window exists. Constructive interference enhance the coupling of bright resonator and dark resonators, resulting in more prominent EIT-like transparent windows, which maybe used for EIT-based optical switch. From the magnetic field distribution, we find that field strongly localized in the cavity, new existing peak is stem from first-order or second-order magnetic resonance, only positive or positive and negative field enhance in two cavities, respectively, the transmission dip, magnetic field only localized in one cavity, which can be used for energy selectively storage. The transmission spectra are very sensitive to the refractive index perturbation, which can be used for highly sensitive sensor.5. The plasmonic resonance properties of the loaded metallic bridge nanoantennas array are investigated. It is shown that the transmission spectra are highly tunable with the variation of the diameter, height and position of the bridge, the diameter and gap distance between adjacent antennas and environmental dielectric parameters. Suitable small metallic bridge is enough to sustain two kinds of resonance modes. Ey field localize on the two outer edge and bridge center, as for second-order mode, the orientation of field is same, when the bridge’s diameter is smaller, more charges concentrate on the bridge center, while when the bridge’s position offset more, the field becomes more diffuse to the arm of nanoantennas, but for the first-order mode, the situation is reverse. These results have reference value for the design of nanoantennas.