The Development Of The Solution Concentration Automatic Control System Based On SPR

In the early 20th century,Wood discovered the surface plasmon resonance(SPR)for the first time,until 1971 Kreschman proposed dielectric-metal-dielectric 3 layers prism coupling model makes SPR to be applied to the sensor field.In 1992,the Dr Jorgenson,university of Washington propose making optical fiber as a carrier to realize SPR.Since optical fiber was developed in sixty or seventy Time of twentieth Century,it has been widely used in communication and sensor because of its low loss,long-distance transmission,miniaturization.The fiber-optic SPR sensor has the advantages of optical fiber and SPR.At present,the automatic control system of solution concentration play an important role in food,chemical and pharmaceutical.In the surface plasmon resonance effect,dielectric refractive index change makes the SPR effect changed.And most concentration of the solution has linear relationship with the refractive index,so we can realize the measurement of solution concentration.First of all,we discussed current development situation and problem of the sensor based on surface plasmon resonance.This paper expounds the sensing principles of surface plasmon resonance from planar waveguide,surface plasma wave,optical excitation surface plasma wave and so on.The basic principle of SPR is light incident to the interface of metal and dielectric than stimulate surface plasma wave,which coupling evanescent waves of the incident light.At last,the reflected light energy is reduced.Secondly,this paper introduces the principle and making process of prism coupling SPR sensor.Using vacuum coating process was introduced in detail;Design the signal amplifying circuit and PCB diagram,and complete the production;Build a full solution concentration of automatic control system combined with signal acquisition card and VB software.Compared with the present industrial plasma resonance sensors,this thesis design the product cost is low,can be widely used in more fields.Finally,we make the tiny SPR sensor with MSM optical fiber as a medium.In glycerin solution for reagent,fitting method for data analysis with the origin to the experimental results.We determine the sensitivity of the sensor can achieve 2500 nm/RIU,which can completely satisfy the required for industrial production.What's more,we used asymmetric coating.For one thing,it reduces the requirement of experimental equipment;For another thing,it broaden the measurement range.