Research Of Surface Plasmons Enhance Fluorescence

Fluorescence technique because of its high sensitivity, the diversity of methods, goodselectivity, and is widely used in biological engineering, medicine and other research work. In thispaper surface plasmon enhanced fluorescence is studied.The resonance characteristics of extinction spectrum are analyzed with the finite elementmethod(FEM) in spherical, spherical core-shell and ellipses core-shell structures. Influences ofmodel parameters, such as radius, thickness and core-shell structure, on the extinction spectra andscattering spectra are studied. Results show that resonance peak of the ellipses core-shell structurecan be more flexible controlled. It will present the blue-shift with the increase of the thickness ofthe sliver nanoshell, while a red-shift with the increase of the aspect radio of the ellipses core-shellstructure. All above can be explained by plasmon hybridization theory and the competitionmechanism between free electrons and oscillating electrons.Two sizes of golden triangle ordered array are made by using nanosphere lithography. CdSe/ZnS quantum dot fluorescence on different substrates is excited by514nm wavelength laser, andfluorescence quenching has occurred. In order to prevent fluorescence quenching, dielectric film iscoated on the metal layer. The result shows that the substrate coated with dielectric film can greatlyimprove the fluorescence enhancement. Using low energy cluster beam deposition based onmagnetron plasma gas aggregation cluster source, the experiment fabricates silver nanoclusters onquartz substrate and measures its transmittance spectrum. Then it disperses SiO2fluorescentnanospheres separately on bare quartz substrates and quartz substrates with silver nanoclusters onthem, it can be found that the fluorescence intensity with silver nanoclusters is5.3larger thanwithout. Finally, it uses Mie scattering theory to calculate the electric field distribution of a singlesilver nanosphere where there is surface plasmon resonance, and comes to a reasonable explanationto the result of the experiment.