Research Of Anomalous Optical Properties Of Multilayer Micro-Nanostructures

Electromagnetic surface waves can be guided at the interface between different materials.There are different types of electromagnetic surface waves depending on the combination of the partner materials.The surface plasmon polaritons,Dyakonov surface waves and Tamm surface waves are three types of most extensively researched electromagnetic surface waves.The coupled surface modes can be modulated by multilayer micro-nano structures,which endows metamaterials with novelty optical properties,such as negative refractive index,perfect electric and magnetic conductivity and hyperbolic dispersion,et.These properties,which cannot be obtained by conventional materials,play substantial roles in the fields of subwavelength imaging,superlens,optical optic camouflage,spectroscopy,optical sensors and photonic integrated circuit,etc.This thesis investigates the modulation of coupled Dyakonov modes guided by symmetric three-layer micro-nanostructures.Under the optical nonlocality condition caused by the coupled surface plasmon mode s,the isofrequency surfaces,refraction and backward Tamm surface waves of multilayer metal-dielectric metamaterials are also analyzed based on the transfer matrix method.The main research contents are as follows:In the research of coupled Dyakonov modes guided by three-layer micro-nanostructures,the eigenvectors of the electromagnetic field in uniaxial materials with optical axis in arbitrary directions are derived.The characteristic matrix and dispersion equation of coupled Dyakonov modes guided by symmetric uniaxial-isotropic-uniaxial micro-nanostructure are deduced.Through the calculation of the dispersions and the attenuation coefficients of each layer,the cut-off conditions of coupled Dyakonov modes are obtained.The modulation of propagation constants,polarization and propagation direction range based on middle layer thickness are analyzed.The field distributions of coupled Dyakonov modes propagating in different directions are investigated.Based on the prism coupling configuration,the polarization conversion caused by the excitation of coupled Dyakonov modes is studied.By taking optical nonlocality into account,the modulation of isofrequency surfaces of multilayer metal-dielectric metamaterials is investigated.Based on the transfer matrix method with periodic boundary condition,the rigorous dispersion equation of transverse magnetic polarized modes of metal-dielectric multilayer metamaterials is inferred.The ellipse-like,Type I and II hyperbolic-like isofrequency surfaces in k-space with different frequencies and structure parameters are calculated.The types of isofrequency surfaces which are beyond the prediction of the effective medium approximation are explored by adjusting the micro-unit thickness.The micro-unit thickness intervals of different types of isofrequency surfaces are investigated and the condition of the related threshold thicknesses is established.The deformation of the isofrequency surfaces caused by metal loss is analyzed.Field distributions are calculated and compared with the result obtained by the effective medium approximation to reveal the influence of surface plasmon modes on the optical nonlocality of multilayer metal-dielectric metamaterials.The refraction of transverse magnetic polarized light in multilayer metal-dielectric metamaterials is also studied.The group velocities are determined according to the isofrequency surfaces,which are applied in the analysis of positive and negative single refraction and negative double refraction when transverse magnetic incident light being input from a homogenous isotropic medium to multilayer metal-dielectric metamaterials.Based on finite element method,these types of refraction are numerically verified.The distributions of the energy flow are also calculated to cl arify the physical mechanisms responding to the negative refraction enabled by ellipse-like and hyperbolic-like isofrequency surfaces respectively.The backward Tamm surface waves supported by multilayer metal-dielectric metamaterials are investigated.Based on transfer matrix method,the dispersion equation of transverse magnetic polarized Tamm surface state guided by the interface between multilayer metal-dielectric metamaterials and a matched isotropic medium is derived.Under optical nonlocality conditi on,the influence of the micro-unit thickness and the sequence of metal/dielectric on the dispersion is investigated.The existence of anomalous dispersions is investigated.The dependence of forward/backward surface waves on surface plasmon modes of the multilayer metal-dielectric metamaterials is unfolded.Finally,the excitations of forward/backward surface waves based on Otto-Kretchmann configuration are numerically simulated through the finite element method.