Regulation The Optical Field Transmission And Coupling Of Artificial Microstructure Metamaterial And Its Application

Metamaterials,constructed of artificial designed unit cells,own the ability to arbitrary adjust the electromagnetic parameters,and hence possess some novel electromagnetic characteristics which are never found in natural materials.As we know,the surface plasmon polaritons is typically utilized to break the diffraction limit due to its smaller wavelength compared with that in the free pace.Therefore,combine the advantages of metamaterials and surface plasmon polaritons,optical devices with characteristics of miniaturization,integration and multi-functionalization can be achieved.In this thesis,by elaborately designing the artificial microstructures,a variety of effects such as plasmon-induced transparency,polarization modulation,beam focusing and polarization resolving were achieved.Moreover,applications of these effect in optoelectronic devices are also investigated.The main content and innovation points are as follows:1.The electromagnetically induced transparency(EIT)-like effect is investigated in a single rectangle resonator modulated MIM bus waveguide system.A modified transmission model with two branches is proposed to characterize the physics of two orthogonal electromagnetic modes formed in the resonator.Close agreement between the analytical results and the finite-difference time-domain(FDTD)simulations verifies the validity of the proposed transmission model.Besides,two different three-level systems mimicking the atomic EIT effect are utilized to further clarify the underlying physics of the plasmon-induced transparency(PIT)effect.It is found that better EIT-like shapes and larger values of group index can be achieved in the horizontal excited system(HES)than in the vertical excited system(VES).The results may deepen the understanding of EIT-like effect and provide a helpful guideline for the control of light in highly integrated optical circuits.2.A conceptually new approach is proposed to design an ultra-thin meta-waveplate(MWP)with anomalous functionalities.By elaborately designing the structural units of the metasurface,the incident right circular polarized(CP)lightcarrying spin angular momentum can be coupled into two surface plasmon modes with opposite orbital angular momenta which interaction with each other in the near-field,degenerating to a linear polarized(LP)light in the far-filed.The incoming spin angular momentum is annihilated and the designed MWP can function as a quarter-waveplate.However,compared with the conventional quarter-waveplates,our designed MWP owns the unidirectional function(only converting CP light to LP light)with a certain output polarization angle,which provides an extra degree of freedoms in controlling the polarization.Moreover,the designed MWP can function as a chiral material and exhibiting optical rotation properties within a broad bandwidth.3.An ultra-thin planar reflective metalens with sub-diffraction-limited and multifunctional focusing is proposed.Based on the equal optical path principle,the specific phase distributions for multifunction focusing are derived.Following the formulas,on-center focusing with the characteristics of sub-diffraction-limited,high focusing efficiency(85%)and broadband focusing is investigated in detail.To demonstrate the flexibility of the reflective metalens,off-center and dual spots focusing(at the horizontal and longitudinal directions)are demonstrated.Note that all these focusings are sub-diffraction-limited due to the evanescent-filed enhancement mechanism in our elaborately designed structure.Moreover,the Numerical aperture dependence on the area of the metalens and their effect on the focusing performance are discussed.4.We propose a novel approach to design an ultra-thin polarization-independent metalens(PIM)by utilizing antennas without rotational invariance.Two arrays of nanoblocks are elaborately designed to form the super cell of the PIM,which are capable of focusing right-handed circularly polarized(RCP)and left-handed circularly polarized(LCP)lights,respectively.With such a strategy,the PIM is able to achieve polarization-independent focusing since the light with any polarization can be treated as a combination of the two orthogonal ones.Further,a theoretical analysis based on the Jones vector is proposed to detailedly explore the underlying physics.The polarization-independent characteristic of the designed PIM is also demonstrated by utilizing the finite difference time domain(FDTD)simulations.Moreover,polarization-independent focusing can be achieved within a wavelength range of400 nm.5.We demonstrate a novel polarization-resolved device(PRD)with the ability to accurately resolve the polarization states via simple measurement process.The PRD is composed of two elaborately designed metalenses,which are capable of focusing the two circularly polarized(CP)lights.Therefore,for an arbitrary polarized light(treated as a combination of the two CP lights),a discrepancy is exhibited on focusing efficiency,which inversely gives a way to calculate the ellipticity.With such a strategy,the generalized form for polarization resolving is derived,with which the ellipticity of the incident polarized light can be calculated(through just measuring the efficiencies of the two spots).This process is accomplished by utilizing the numerical simulations and theoretical analysis.Further,polarization states resolving can be achieved within a wavelength range of 400 nm,due to the broadband effect of the designed metalenses.