Research On Photoseparation Devices Based On Surface Plasmon Polaritons

Surface plasmon polaritons is a kind of non-radiative electromagnetic waves in hybridstate,which is restricted along the surface by the collision of the metal after the oscillation of freeelectrons of the metal surface with the incident photon. Use this theory to design and researchspectroscopic device.The main works and researchs in the following aspects：1.Firstly,describe the significance of the topic and introduce the development and relatedapplications of SPPs.Then, analysis the theory of finite difference time domain method andcalculate the corresponding parameters of gold in different bands based on metal drude modeltheory. Derive the formulas of dispersion relation and characteristic parameters and research the theexcitation.principles and main characteristics of SPPs.2.Analysis the excitation mechanismof Kretschmann structure,then, based on formula ofreflectivity,research the influence of excitation angle, dielectric material and thickness of metalfilm on the excitation.Determine the parameters and the minimum interval, introducing sharpnessformula to search to get the best combination of parameters of each light band in500nm~1000nm.Select parameters of0.6526μm to simulate Kretschmann three media model，from attenuationand maximum depth of field position to verify the correctness of the parameters. Finally, design andsimulate of a cascaded photoseparation device with0.5904μm,0.6526μm,0.7293μm, analysis thespectral performance.3.For the shortcoming of cascaded splitter device with more structure element,find the waveswhich does not excite SPPs in the standard configuration remain the original direction ofpropagation when out of the structure. Simulatie and study the SPPs excitation process,light pathand loss of light intensity in each position of structure with parameters of0.6888μm. Forcomparison,the actual spread of the optical path of the light intensity at each position and thereasons for the loss. For comparison,also designed a tandem photoseparation device based on0.5904μm,0.6526μm,0.7293μm, then simulate and study its spectral properties.Finally, compares the performance of the two devices and summary that cascaded device hashigh spectral efficiency,but much structure element number, the tandem structure has fewer elementbut actual production is difficult. Meanwhile, summary the problems in simulation and analysis related reasons,then point out it can be applied to WDM system, to separate a variety of mixedlights.