Study On The Novel Structure Filter Based On Surface Plasmon Polaritons

With the rapid development of communication technology,people's demand for information transmission rate,storage capacity and miniaturization of optoelectronic devices is increasing.However,the diffraction limit of optics limits the performance improvement and size reduction of traditional optoelectronic devices.Surface Plasmon Polaritons(SPPs)are electromagnetic waves that propagate along the interface between metal and medium,which can break through the diffraction limit of optics and manipulate light at micro-nano wavelengths.Therefore,optoelectronic devices based on SPPs are widely studied.Among them,SPPs-based filters are important devices for wavelength selection.However,common filters are prone to several problems: the transmission spectrum is not smooth enough,the passband transmittance is not high enough,the stopband transmittance is not low enough,it can't be flexibly applied to the three communication windows,and it can't be realized electrically adjustable.In order to solve above problems,this thesis mainly constructs two kinds of filters based on SPPs,the filters proposed can be used in the research of high-density integrated optical devices and nano-optics,it has important application value in optical communication systems.The main research contents of this thesis are as follows:First,the boundary coupling method is used to construct a metal-insulator-metal(MIM)arch-type resonator filter based on Surface Plasmon Polaritons,this filter is composed of a rectangular waveguide and an arch-type resonator.The finite element method is used to study the transmission line and resonance wavelength of the filter,the formation principle is analyzed in combination with the magnetic field distribution diagram.The research results show that the transmission spectrum is smooth and the bandwidth is wide(full width at half maximum reaches 718 nm),the transmittance of the passband is as high as 0.976,and the transmittance of the stopband is as low as 0.001,the filter can be used as a band-stop filter with excellent performance.Then the parameters of the arch-type filter are optimized,based on the original structure,two optimized structures are further designed,one can be used as a Fano resonance structure,and the other can be used as a band-pass filter.Second,the aperture coupling method is used to construct a MIM asymmetric rectangular ring resonance cavity tunable filter based on Surface Plasmon Polaritons,the filter is composed of a rectangular waveguide and two rectangular ring cavities.This structure filter adopts an organic electro-optical material 4-dimethylamino-N-methyl-4-stilbazolium tosylate(DAST)whose optical characteristics change with the applied voltage,fill it into the asymmetrical rectangular ring cavity to realize the electrical adjustable function of the filter.The finite element method is used to analyze the performance of the structure filter,the research results show that its passband bandwidth(full width at half maximum reaches 880 nm)and stopband bandwidth(full width at half maximum reaches 50 nm)are relatively wide,the transmittance of the passband is as high as 0.97,the transmittance of the stopband is as low as 0.0001.The asymmetric rectangular structure filter can not only adjust the filter characteristics by changing the structural parameters,but also adjust the filter characteristics by applying a control voltage,the filter can be used as a band-pass and band-stop hybrid filter.The asymmetric rectangular structure is further optimized,and the designed symmetrical multiple rectangular ring cavity filter has a wider stopband(full width at half maximum reaches 100 nm),this structure can also be used as an adjustable band-pass and band-stop hybrid filter.