The Study About Ehancement Of Magnetic Dipole Emission At Yellow Light In Optical Metamaterials

Metamaterial is a kind of artificial synthetic material, which is made up of micro-nano periodical units and own speci al properties. By ways of designing different unit structure and size parameters, w e can adjust the permittivity and permeability to realize phenomenon like negative refraction, super resolution imaging and optical stealth. While so-called magnetic metamaterial can make the effective permeability of the structure not be one at some frequency, w hich is because that it forms a certain magnetic resonance and create magnetic ho t spots around. According to Purcell effect and the Fermi gold law, the magnetic resonance can change the density of surrounding states, and have a influence on the efficiency o f dipole transition in space. It is based on this reason that using the resonance effect of metamaterial to control spontaneous emission of the dipole has become a hot spot in the field of materials. Based on resonance theory about magnetic metamaterial, the study uses finite element simulatio n software to study the dipole spontaneous radiation and fabricate inorganic an d organic rare earth material which includes magnetic dipole transition around 590 nm.In this study, the Ag-Al2O3-Ag sandwich grating structure is designed by using numerical simulation method, and the resonance position and intensity is studied under TE and TM mode. It is demonst rated that a TM mode incident field can form a strong magnetic resonance in sandwich structure. By using a single variable to study the influence of structural parameters on the magnetic resonance effect, we optimized the size, and confirmed that structure width is the decisive factor to control magnetic response. The field enhancement effect is obtained by 80 times at 590 nm in the structure; Through the reappearance of the literature results,we determine the method calculation of Purcell factor and radiation enhancement factor. By this method, the magnetic dipole Purcell factor and radiation enhancement factor reached 175 t imes and 90 times at 590 nm magnetic resonance, which is never achieve d in visible light wave band; By changing the structure width and the position of the magnetic dipole, the enhancement of the magnetic dipole radiation is proved to be insensitive about the size and space of the sandwich grating structure.In experiment, the inorganic rare earth luminescent powder Y2O3:Eu3+ was fabricated by combustion synthesis method, and the laser at 320 nm can excite the magnetic dipole transition peak near 590 nm; organic rare earth complexes, Eu(HFA) 3 was synthesized by heating method and comparing to Y2O3:Eu3 +, the magnetic dipole radiation spectrum line is more broadband around 590 nm, which is more suitable for the following experiment s. Finally according to the size and structure characteristics of sandwich structure, we design ed two basic processes for fabrication process, including etching and lift-off method.