Research On Waveguide Sensors Based On Localized Surface Plasmon Resonance Effect

Due to the potential application value of the localized surface plasmon resonanc(Localized Surface Plasmon Resonance,LSPR)effect of precious metals particles in the sensing field,it has become a hotspot in the field of photoelectron sensing in recent years.The sensors based on LSPR effect have the advantages of low preparation cost,high sensitivity and quick response,which can play an important role in biomedicine,drug detection,food safety and environmental testing.This paper summarizes the research of the predecessors,and fuse the optoelectronic technology,biomedical technology,nano-science and technology,while the mechanical properties and optical properties of the polymer is played.The polymer optical waveguide sensors based on the LSPR effect of gold nanoparticles are presented,which is characterized by low cost,high integration and portability,and can be composed of photonic sensing chips with different structures and kinds of waveguide devices.This paper studies the polymer optical waveguide sensors based on the LSPR effect of gold nanoparticles in the aspects of theoretical simulation,material preparation,device fabrication and performance testing,and the main work is as follows:1.The influence factors of LSPR effect of gold nanoparticles and gold nanorods are analyzed by using the Mie theory model and Gans theory model respectively.The results show that the strength of LSPR absorption peaks of gold nanoparticles is enhanced with the increase of the bulk density,particle size and the refractive index of ambient media in the gold nanoparticles.And the increase of the size of gold nanoparticles and the refractive index of the ambient medium can also lead to the red shift of the LSPR absorption peaks of gold nanoparticles.While the diameter of the particle changes by 10 nm,the location of LSPR absorption peaks shift by 7.7 nm averagely.When the refractive index of ambient dielectric changes by 0.03,the location of LSPR absorption peaks shift by 3.5 nm averagely.In addition,with the increase of the refractive index of the ambient medium and the ratio of the length and width of in the gold nanorods,the LSPR absorption peaks of the gold nanoparticles are red-shifted and the intensity increases.When the ambient dielectric refractive index changes bye 0.5,LSPR absorption peaks shift by 31 nm averagely.When the ratio of the length and width changes by 0.5,LSPR absorption peaks shift by 44 nm averagely.2.The gold nanoparticles with 20 nm diameter,homogeneous morphology and better dispersion are made by the method of sodium citrate reduction method.Gold nanoparticles are binded on the surface of the polymer SU-8 film by using silane self-assembly monolayer technology(Silane Selfassembled Monolayer,SMA).The LSPR absorption tests of polymer SU-8 film are made by using UV-Vis spectrophotometer.It is found that the strength of LSPR absorption peaks of gold nanoparticles increases with the time of chemical modification of the polymer SU-8 film and the binding of gold nanoparticles on the polymer SU-8 film.3.The polymer SU-8 films bonded with gold nanoparticles are tested in different concentrations of NaCl and sucrose solutions.When the refractive index of 5%,10%and 20%NaCl solution changes by 0.0135 averagely,the location of LSPR absorption peaks shift by 5.5 nm averagely,and the sensitivity is 314 nm/RIU.The red shift change of location of LSPR absorption peaks is linearly increasing with the increase of the refractive index of NaCl solution.The linearity is 0.9977.When the refractive index of 20%,400%and 60%sucrose solution changes by 0.039 averagely,the location of LSPR absorption peaks shift by 6.5 nm averagely,and the sensitivity is 168 nm/RIU.The red shift change of location of LSPR absorption peaks is linearly increasing with the increase of the refractive index of sucrose solution.The linearity is 0.8708.4.Polymer optical waveguide sensors based on gold nanoparticles are designed and fabricated,and the optical test system and the sensing detection system of the optical waveguide sensor are constructed.In addition,the devices with no gold nanoparticles are prepared to verify the effect of gold nanoparticles on the performance of the sensors.Compared with the device with no gold nanoparticles,the apparent LSPR absorption peaks are found by the device with gold nanoparticles when detecting different concentrations of NaCl solution and sucrose solutions.The absorption strength increases by 0.069 when the concentration of NaCl solution increases from 5%to 25%,and the sensitivity is 1.863 A/RIU.While the concentration of sucrose solution increases from 20%to 60%,the absorption strength increases by 0.030,and the sensitivity is 1.065/RIU.