Simulation Of Aluminum Plasmonics In Magneto Optical Systems

Plasmonics combined with magneto-optical system is a new way to study magnet optics.With the electromagnetic energy concentrated by the plasmonic,the sub wave length magnet optics can be clearly observed,so that the MO system can be proper nanostructured and integrated.By this method,vivid types of optic devices are made constantly,such as new type of biosensors and isolators.Therefore,noble metals are used as significant plasmonic providers in MO system.Here we introduce another plasmonic metal,Al,which is recently in the view of relative researchers.In this paper,we designed a system which combines Al plasmonic with magnet material,Bi:YIG,and calculated with FDTD solutions.In compared with the date calculated by noble metals system in same structure,the potential that Al plasmonic in MO is finally revealed.In this paper,we mainly work on the following two points:1.The Faraday effects calculation of metal film perforated with nanohole arrays and Bi:YIG We used FDTD to calculate the Faraday effects of systems which combine metal film perforated with nanohole arrays with Bi:YIG.With the selection of gold,silver and aluminum,we collect the data of transmission and Faraday rotation degree.After comparison with noble metals,the performance of Al in our system can be easily obtained.The calculation shows that: when the initial light is in the wave length range of 550 nm to750nm,the gold film performs excellently,the aluminum film has a bit lower date of MO spectrums than silver film.While in the range of 350 nm to 550 nm,the gold films basically provided no help in MO system,the silver and aluminum films perform large enhancement in spectrum.Therefore,we can see the potential and practical value of Al plamonic structure in MO system.2.the Faraday effects calculation of oxidized Al film and dielectric magnetized film with the same structure we used in the previous work,we added different thicknesses of aluminum oxide surrounding the Al film,so that the performance of oxidized Al in MO system can be obtains.In our calculation,Al oxide perform red-shift on the spectra of both transmission and Faraday rotation,moreover,the transmission enhancements is observed in the spectra,while the faraday rotation is in the opposite way.Theoretical analysis shows that the oxide weakens the LSPR of aluminum film,changes the periods of SPP and Fabry-Perot effect,and therefore the spectrum are different from the pure Al film.Based on the work have been done,we conclude that: 1.Al plamonic-MO structure is sensitive to oxidation,which is easily observed due to the red-shift on the spectra.We can even estimate the content of aluminum oxide from the red-shift.2.oxide layer enhance the transmission of light and weaken the MO Faraday effect.This support the MO device from the theory side.