Surface Plasmon Resonance, Theoretical And Experimental Study

As a physical optical phenomena, surface plasmon resonance (SPR) is discussed inthis paper both in theory and in experiment. The work is valuable to setting up a opticsmodel to test the complex refractive index of biological tissues, and eventually achieve it.Originated from Maxwell's theory and Drude model, we discussed the physical modelof surface plasmon wave and surface plasmon resonance under different conditions.Specially of metal thin-film structure, we study the propagation characteristic of SPWintensively, and carry out theoretical simulations according to ideal model and practicalmodel respectively under different thickness of the film and the wavelength of probe beam.Using a normalized convolution method and an angular spectrum decompositionmethod, we calculate the reflection curves of the divergent probe beam with uniformintensity distribution. The calculated results show that with the increasing divergencyminimum reflectivity increases, resonance width broadens and resonance angle increases.A uniform intensity distribution divergent probe beam with a divergent angle of 4mrad willinduce a resonance angle error of 1.9×10^-3degree. Furthermore the broadening ofresonance width will increase the random error. And the experiments verify the results ofthe simulation.It is proposed that the phase measurement is more sensitive than that of theconventional angular detection that is usually used in the affinity biosensors. So we studythe phase property using elliptical polarization method. We set up the model first, carry outsome simulations, and then the experiments verify the results of the simulation perfectly.The optical setup is simple.Using surface plasmon resonance technology to test the complex refractive index ofbiological tissues is still a groping work. Other problems such as the completion of mathmodel and the construction of a automatized experimental hardware are necessary to bestudied in future work.