Backward-Propagating Surface Plasmon Resonance Mode And The Research On Bio-Laser

Surface plasmon resonance(SPR)is a physical process of plasmons exciting,because of the special optical properties of metal,the surface plasma wave(SPW)can transmit on metal and medium interface.This kind of surface wave has a wide effective refractive index existence and a strong field enhancement effect.It is a challenge for how to improve the coupling efficiency of SPR and take charge of its directional.Making the SPR sensor by using this principle is become a research focus.Based on the principle of SPR,this paper demonstrates backward propagating SPR mode and gives the logical production mechanism: the backward propagating mode is caused by Mie scattering of SPW.We analyze the application of this phenomenon in sensing.The mechanism of backscattering is used to increase the sensor efficiency.In this work,we use the method of prism coupling and evaporate a silver film on it in vacuum.Exciting the SPR on the surface between silver film and air.Because of the coating technology,there are silver particles on the silver film so that the SPW will be scattered by them and we make sure it is the Mie scattering.That causes two light arcs on the light screen.Using this phenomenon,we can make a new plasma coupler,which can overcome the limitation of excitation direction and limitation of detection range in the sensing field,and can be widely used in biosensor systems.On this basis,the SPR can combine with biological laser.We improve the experiment on the basis of using waveguide,combine SPR with chlorella to excite the laser and because of the bi-direction of SPR,it can increase the efficiency of the laser exciting.