Fiber Surface Plasmon Research

Surface plasmon polaritons detection technology is increasingly mature,with its high sensitivity,rapid detection,less sample consumption,application in the fields of biology,chemistry,imaging and detection is also more and more,has become a high sensitivity optical detection technology.Therefore,SPR technology has been widely used and developed,derived a number of methods to excitation the SPR,such as the prism to excitation SPR,optical fiber excitation SPR,optical waveguide excitation SPR,the objective lens SPR.Each excitation SPR method has its own advantages and characteristics.For the prism excitation SPR,the experimental system is simple in structure,easy to build,easy to operate,and the light intensity and angle modulation data can be easily achieved by the optical power meter and micro displacement platform.The optical excitation of the SPR method requires the laser and detector optical devices have optical fiber interface convenient experiment.The two of them have little difference in the sensitivity of refractive index detection,but because of the small size of the optical fiber,it can be detected in a specific environment,so it is widely used in the field of SPR detection.Based on the SPR theoretical derivation and the simulation experiments of Matlab and LabVIEW software,we try to find the relationship between the SPR curve and the parameters under different conditions by changing the refractive index of the medium,the incident wavelength and the thickness of the film.This paper first introduces the origin,development of SPR and summarizes the status.Then the formula is deduced from the theoretical basis,and the calculation formula of the reflectivity is obtained,Simulation of SPR in optical fiber by software.The simulation results of different membrane structures are summarized,and the different SPR phenomena of gold,silver,aluminum,copper and other materials under different film thickness are obtained.At the same time,the influence of the incident wavelength,the refractive index of the medium and the thickness of the film on the SPR curve is studied.It is concluded that the minimum value of the reflectivity decreases with the increase of the real part,the imaginary part becoming smaller and the film thickness thicker,after reaching extreme value,with the increase of the real part,the imaginary part becomes smaller,the thickness of the film becomes thicker the reflectivity is more and more big.With the increase of the real part,the imaginary part becomes smaller,the film thickness thicker,the absorption peak becomes narrower and narrower,and the SPR phenomenon is more and more obvious.On the basis of the gold film,further simulation of the resonance angle of fiber SPR is 45 degrees,When the refractive index of the film is-20.98,the imaginary part is 0.856,and the film thickness is 56.2nm,the minimum reflectivity is at the wavelength of 850 nm,good fiber SPR simulation curves are obtained.Finally,the possible errors in the experiment are analyzed.