Mode Coupling And Absorptions In Various Order Plasmonic Micro-nano Structures

The concepts of order and disorder are commonly used for describing the symmetry or correlation properties of systems constructing from a large amount of units. The ordered system can be characterized by long range order or short range order according to the non-localization or localization of the symmetry or correlation properties. With the rise of the study of the photonic crystal, these concepts are also expanded to describe the artificial metamaterials in optics. In this paper, we introduce metal into the structures with different orders and study the excitation, mode coupling, high efficient absorption, broadband multiple response and analogy electromagnetically induced transparency relating to the surface plasmon polaritons(SPPs) in the periodic, quasiperiodic and disordered structures. The nonlinear phenomena of mode coupling and lower threshold optical bistability are also the subjects we investigate.In the 1D metallic photonic crystal, we further investigate the derivation among the resonant modes, long-range/short-range plasmon polaritons(LRPs/SRPs) and bulk plasmon polaritons(BPPs). The discrete property of BPPs could be understood by analyzing BPPs using the Bloch evanescent wave together with the Born-von Karman boundary conditions. The graphene/dielectric multilayer system is also studied and the similar modes to the SRP and BPPs are found. Besides the symmetric and antisymmetric mode, an asymmetric mode is obtained in the graphene/dielectric/graphene structures, when graphene nonlinear is considered. It results from the rebalance of the prorogation constant changing induced by graphene nonlinearity and mode coupling process.Secondly, the excitation of SPPs in the periodically corrugated metal film structure is studied. The SPPs is found to be able to excited on the upper and lower metal surface independently, simultaneously. The dispersion relations simply cross each other. In the near THz range, the graphene surface plasmon(GSP) can be excited in the graphene-covered binary grating structures. The excitation frequency is determined by the phase matching conditions and influenced by the coupling between GSP on the adjacent graphene layers.The excitation intensities are found to be relative to the structure parameters, including the duty ratio and grating thickness. A broadband absorption is obtained in the multilayer graphene structures with the frequency belong to 5～12THz.Quasicrystal is a structure with long range order but lacking of periodicity. The sacrifice of short range order brings us more abundant reciprocal vectors with multiple symmetry and self-similarity. Whether a structure contains the long range order is confirmed by its diffraction patterns. The long range order focuses on the correlation or symmetry divided by a large distance, while the short range order focuses on the localized periodicity. The RCWA(Rigorous Coupled Wave Analysis) method is improved to be able to handle the quasicrystalline structures, the keys of which are the assembly of the material matric and choice of base vectors. Then, the multiple responses in the 2D quasicrystalline plasmonic structures is obtained for both TE/TM modes with wavelength in 0.5～1.2μm,caused by the multi-fold symmetry of the reciprocal vectors. The coupling properties between these modes are also presented.The randomly layered media is one of the main subject in studying the disordered media, which is a two-component multilayer structure with the randomly varying thickness. The inverse localization length is used to characterize its localization properties.The semi-analytical result of inverse localization length was found under the weak disorder condition. Under the strong disorder condition, the inverse localization length exist a full analytical result. With the increase of distribution with of random thickness, the inverse localization length is found to fluctuating around the limit value of strong disorder and the amplitude tends to zero in the limitation. Increasing the difference of refractive indexes between the components can also enhance the localization property. For the multicomponent randomly layered media, the arrangement and their proportion are found playing an important role, especially for weak disorder condition. It is found that the Tamm plasmon polaritons(TPPs) can also exist in the metal/randomly layered media structure.Analogy electromagnetically induced transparency is realized in the metal/photonic crystal/randomly layered media structure for the high Q factor of resonance. Low threshold optical bistability(～44k W/cm2) is also obtained in the metal/randomly layered media structure, due to enhancement of the TPPs and the abnormal resonant transmission.