Design And Simulation Of Optical Sensor Based On The Principle Of Surface Plasmon Resonance

With the advent of the information age,sensor technology has been an unprecedented development and application,so as to meet the growing need for cognition.Compared with traditional optical sensors,the optical sensors based on surface plasmon resonance(SPR)are good candidates for medical diagnosis,biochemical sensing and other fields due to their advantages of good integration,high sensitivity and flexible design.In this thesis,based on the theoretical analysis of SPR,the metal micro-nano structure SPR sensors and side-polished fiber-optic SPR sensors are designed and analyzed via the Finite-Difference Time-Domain(FDTD)and Finite Element Method(FEM).The major research works of the thesis are as follows:(1)Based on FDTD,two SPR sensors with metal micro-nano structure are designed,and their optical sensing characteristics are studied and analyzed.The one of structures contains a three-tier metamaterial absorber that is composed of periodically-permutated silver nanodisks,aluminum oxide(Al₂O₃)and silver film.Our result in simulation showed that the light absorption of the structure is as high as 99.6%in the visible light band,and the refractive index sensitivity is adjustable with thickness of the silver nanodisk.The another structure includes a surface plasmon sensor that is composed of a resonant cavity embedded with silver nanorods and a straight waveguide.The structure realizes refractive index sensing and temperature sensing in the wavelength range of 500?3500 nm,with a refractive index sensitivity of 2116.73 nm/RIU and a temperature sensitivity of 0.98 nm/?,which is apply for low temperature sensing and environmental refractive index measurement.(2)Two fiber optic SPR sensors are designed based on FEM.The first structure contains an all-solid-state D-type photonic crystal fiber sensor with the principle of SPR.The fiber sensor structure uses two solid dielectric rods with a larger radius on the X axis as to introduce birefringence,the lateral polishing fiber is thus used for addressing the problem that leads to analyte filling from PCF-SPR sensors.In addition,a side-polished panda optical fiber sensor is proposed and prepared.The results from experiments showed that the structure achieves a refractive index sensitivity of up to 3100 nm/RIU,which is applicable for environmental sensing measurement.