利用相位解卷绕法修正SPR相位解调的研究  

Phase Demodulation Correction of Surface Plasmon Resonance Based on Phase Unwrapping Method

作　　者：朱云浩 胡淼森 邓硕 袁继宪 吕海飞 黎敏[1] Zhu Yunhao;Hu Miaosen;Deng Shuo;Yuan Jixian;LüHaifei;Li Min(School of Science,Wuhan University of Technology,Wuhan 430070,Hubei,China;Liangyuan District Institute of Science and Technology Information,Shangqiu 476000,Henan,China)

机构地区：[1]武汉理工大学理学院,湖北武汉430070 [2]梁园区科学技术局科学技术情报研究所,河南商丘476000

出　　处：《光学学报》2023年第20期233-240,共8页Acta Optica Sinica

基　　金：国家自然科学基金(11974266,62075174)。

摘　　要：相位型表面等离子体共振(SPR)技术具有极高的检测灵敏度。然而,理论求解SPR信号的相位差时通常会出现相位跳变的情况,致使理论与实验结果不能直接对应,需要人为修正。提出一种新的相位求解方法——相位解卷绕法,通过不同厚度金膜修正前后的SPR相位差的计算结果与实验结果对比表明:相位解卷绕法修正后的解调结果不再出现相位跳变现象;且相位差变化量随金膜厚度的增加呈先增加后减少的趋势,即存在一个对应于相位差极大值的最佳金膜厚度。相位解卷绕法解决了SPR相位解调中的相位跳变问题,使理论计算能直接对应实验结果。Objective Surface plasmon resonance(SPR)technology features high sensitivity,fast response speed,and stable measurement results,and is widely applied in the fields such as biomedical and nanomaterials detection.According to the signal modulation methods,SPR sensors are classified into four types of intensity modulation,wavelength modulation,angle modulation,and phase modulation.Compared with other modulation methods,phase modulation SPR has higher sensitivity.When SPR occurs,the phase of the p-polarized light changes greatly near the resonance angle,and its detection sensitivity is usually two-three orders of magnitude higher than that of other types of SPR sensors.However,previous literature reported phase jumps in the calculated phase sensitivity of prism-structure SPR,and the maximum sensitivity obtained from this calculation is not achievable in practical measurements.Further research and analysis prove that the appearance of jumps is due to the utilization of the arctangent function in calculating the phase angle.When the phase value of an angle infinitely approaches-π,the subsequent angle's phase result jumps toπ,which causes an increase in the phase differences between the two angles and the occurrence of phase jumps.We solve the phase jumps by introducing the phase unwrapping function during calculating the phase angle and correct the calculation results of the phase difference of three gold films with different thicknesses.At the same time,the SPR phase demodulation method based on the Mach-Zehnder interferometer is optimized,and the correctness of the phase unwrapping method is experimentally verified.Our proposed method is expected to provide an optimized solution for the design of phase-type SPR sensors.Methods We propose a phase unwrapping function to solve phase jumps.The basic idea is to employ phase continuity to determine the location of the phase wrap by comparing the values of two adjacent phases in the calculated phase function results,and then adopt the phase unwrapping function to unwrap t

关 键 词：表面等离子体共振 相位解调 相位解卷绕法 干涉测量 金膜 

分 类 号：O436[机械工程—光学工程]