Research On Sensing Of Chirality Parameter And Refractive Index Based On Fibers

The theoretical research,simulation design and experimental verification of surface plasmon resonance(SPR)for parameter sensing,have always been research hotspots in biomedicine,optics,electromagnetics,and other fields.This thesis mainly discusses the principle and sensing characteristics of the optical fiber chirality parameter sensor based on the surface plasma resonance.The structure and method of realizing the simultaneous sensing of the chirality parameter and the refractive index are proposed.The main research results of this thesis are as follows:1.Based on the theory of surface plasmon resonance,the principles and method of realizing the chirality parameter sensing with SPR optical fiber sensor are studied.The wave equation of chiral drugs with the constitutive relation of Pasteur chiral medium and the weak expression of wave equation for the chiral medium are derived.Then the wave equation is programmed into the finite element method software COMSOL Multiphysics.,The specific structure and sensing characteristics of SPR fiber are discussed based on the software.2.Based on the optical fiber theory,the optical mode and dispersion characteristics of a D-type single-mode SPR based optical fiber immersed in chiral medium are studied.The sensing characteristics of chirality parameter and refractive index of the structure are discussed.The influence of the chirality parameter on the confinement loss of the optical fiber propagation spectrum is also discussed.Then,taking the sensor parameters such as sensitivity and resolution as the indices,the effects of different metal layer,metal layer thickness,and polishing depth on the sensing characteristics of the chiral parameters are simulated.3.Based on the theory of photonic crystal fiber(PCF),the optical mode and dispersion characteristics of D-type PCF immersed in chiral media are analyzed.The sensing characteristics of chirality parameter and refractive index of the structure are discussed.The influence of the chirality parameter of the structure on the confinement loss of optical fiber propagation spectrum is researched.The sensing effects of the D-type PCF are compared with those of the D-type single-mode optical fiber.Then,taking the sensor parameters such as sensitivity and resolution as indices,the effects of different metal layers,metal layer thickness,and polishing depth on the sensing characteristics of the chirality parameter are simulated and analyzed.4.The two parameters,chirality parameter and refractive index,have the same trend in the shift of the resonance peak.Furthermore,the graphic method of realizing the simultaneous dual-parameter sensing is investigated based on the simulation datas of two different sensitivity optical fiber sensors.The steps of realizing the two parameter sensing with two different structures and sensitivity sensors are illustrated as an example.