| Metamaterials is an emerging field in the academic research,especially in materials science areas.It is a kind of sub wavelength micro structure,which is artificial rather than natural materials.In recently years,with the growing related papers are published in this area,metamaterial science attracts more attentions.Unlike other natural substances,metamaterials exhibit some unique physical properties,like the permittivity and permeability.It has gained more and more attentions of scientists.As a new branch of material science,the metamaterials provide a broader prospect for the development of many subjects,such as optics,physics,electronics and so on.Magnetic resonance metamaterials are emphasizing more on the electromagnetic properties.Because of the different geometrical characters of the structure,magnetic resonance metamaterials can form the hot magnetic field.According to this principle,the resonant characteristics of structural units can be formed,which can effectively enhance the magnetic field or electric field localized near the surface of the structures.In addition,different geometry parameters of the structures have different effects on the magnetic field and electric field,so it can be adjusted by the structural parameters to obtain the specific characteristics of the material.In this thesis,we design the metamaterials with the structure of grating-medium-metal,in order to get stronger magnetic coupling(magnetic field resonance)by optimizing the key parameters.In this way,we can achieve the target of regulating the magnetic field or electric field.In the study,considering with the position of magnetic resonance of the metamaterial,this paper proposed the idea of combining the magnetic resonance with the dipole transition of the magnetic material rare earth Eu firstly.This experiment use the finite element electromagnetic simulation software COMSOL Multiphysics,by the following steps,like modeling,properties setting of material,mesh definition and calculation,we can design the structure with grating–medium-metal composite metamaterials.And with these steps,including simulation and optimization of the parameters,the most optimum size can be determined.In this structure,one metal layer is made of silver and metal layer are silver grating and silver film.The silver grating and layer are prepared by electron beam lithography.The medium layer is a mixed film with rare earth Eu and PMMA.This paper uses organic and inorganic methods to prepare the dielectric layer respectively,and finally chosed the organic method to prepare the medium layer for its more efficient lighting.The enhancement intensity of the magnetic-metamaterial structure for the excitation luminescence of Eu3+ are tested by the following way.The medium layer which is embedded with active molecules Eu3+ is pumped by femtosecond laser with wavelength of 400 nm.And by detecting and collecting of emission spectra of composite structure and comparing with the spectrum of the structure just with PMMA,we can get the enhancement intensity of the prepared magnetic luminescence.By embedding active molecules Eu3+ into the structure of the metamaterial,the magnetic dipole emission can be increased by 4.7 times.In this paper,the phenomenon of electromagnetically induced transparency(EIT)of silver grating is observed in the experiment.And the phenomenon electromagnetic induced transparency was systematically studied in this thesis.The phenomenon is measured by the transmission and reflection spectra of the grating structure with different periods,mainly through the changing incident angle.And according to the data analysis,this paper analyzes the changes of electromagnetic wave coherent coupling and electromagnetic induced transparency. |
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