基于液晶回音壁模式传感的光谱标定方法研究  

Research on Spectral Calibration Method Based on Liquid Crystal Whispering Gallery Mode Sensing

作　　者：麻镇宇 李晓强 刘永军 严云翔 MA Zhen-yu;LI Xiao-qiang;LIU Yong-jun;YAN Yun-xiang(Key Laboratory of Fiber Integrated Optics,Ministry of Education,Harbin Engineering University,Harbin 150001,China;Key Laboratory of Marine Photonic Materials and Device Physics,Ministry of Industry and Information Technology,Harbin Engineering University,Harbin 150001,China;Qingdao Innovation and Development Center,Harbin Engineering University,Qingdao 266000,China)

机构地区：[1]哈尔滨工程大学纤维集成光学教育部重点实验室,黑龙江哈尔滨150001 [2]哈尔滨工程大学海洋光子材料与器件物理工业和信息化部重点实验室,黑龙江哈尔滨150001 [3]哈尔滨工程大学青岛创新发展中心,山东青岛266000

出　　处：《光谱学与光谱分析》2025年第1期30-37,共8页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(12103015);哈尔滨工程大学博士研究生科研创新基金项目(KCWL202301)资助。

摘　　要：液晶回音壁模式(WGM)传感技术结合了液晶材料的高敏感性和光学WGM的高精度特性,在物质检测、环境监测和生物医疗等领域具有广阔的应用前景。为提升传感测量的精度和灵敏度,除了改善传感器的结构特性以外,如提高品质因子、实现窄线宽、提升波长移动范围等,准确标定WGM光谱谱线是一个重要内容。然而,实际应用中,WGM光谱的非规则分布给谱线标定带来了挑战。本文针对此问题提出了一种基于Savitzky-Golay(SG)滤波和高斯平滑的WGM非规则光谱标定方法,并提出了光谱标定的对称性、高线性和合理性三原则。将WGM光谱标定分为规则和非规则两类。对于规则光谱,具有良好的洛伦兹线型和高斯包络轮廓,可以选择最高强度谱线或中心波长,或者具有相同自由光谱范围(FSR)的相邻模式谱线作为谐振波长。而对于非规则光谱,可以分为三类:(1)光谱缺峰和强度突变,主要由于谐振条件的损耗变化所致;(2)光谱非规则劈裂,液晶微腔中可能存在微小的缺陷或杂质,导致光谱的非对称劈裂;(3)混合型变化光谱,受到复杂测量环境的影响,可能出现多种不规则变化。通过SG滤波和高斯平滑处理,有效地恢复光谱的对称性,提升拟合线性度,实现光谱标定。为验证该方法的有效性,根据不同类型光谱标定情况,分别设计了利用液晶WGM对不同生物分子的传感实验,包括胰蛋白酶(浓度0.75~2.00μg·mL^(-1))、pH(4.55~6.86)、DNA(浓度90~490μg·mL^(-1))等。实验结果表明,采用本文方法和三原则进行液晶WGM光谱标定和谐振峰选取,传感灵敏度的线性度均在0.99以上,具有较好的可靠性和稳定性。该研究创新之处在于提出了针对液晶WGM光谱非规则分布的有效标定方法和三原则,为提高液晶WGM传感测量的准确性和有效性提供了有效解决方案和重要的理论和方法支持,具有重要的应用和理论意义。Liquid crystal whispering-gallery-mode(WGM)sensing technology combines the high sensitivity of liquid crystal materials with the high precision characteristics of optical WGM,holding broad application prospects in substance detection,environmental monitoring,and biomedical fields.To enhance the accuracy and sensitivity of sensing measurements,accurate calibration of the WGM spectral lines is crucial.However,the irregular distribution of liquid crystal WGM spectra poses challenges to spectral calibration in practical applications.This paper proposes a method for calibrating irregular liquid crystal WGM spectra based on Savitzky-Golay filtering and Gaussian smoothing,advocating three principles of symmetry,high linearity,and rationality for spectral calibration.Spectral calibration is categorized into regular and irregular spectra.For regular spectra with good Lorentzian line shapes and Gaussian envelope profiles,the highest intensity spectral line,central wavelength,or spectral lines of adjacent modes with the same free spectral range can be selected as the resonance wavelength.For irregular spectra,three types are identified:(1)spectral missing peaks and intensity variations mainly caused by loss variations in resonance conditions;(2)spectral irregular splitting due to small defects or impurities in the liquid crystal microcavity,leading to asymmetric splitting of spectra;and(3)mixed-type variable spectra affected by complex measurement environments,resulting in various irregular changes.Through Savitzky-Golay filtering and Gaussian smoothing,spectral symmetry is effectively restored,and fitting linearity is improved,facilitating spectral calibration.To validate the effectiveness of the proposed method,experiments are designed for sensing different biological molecules using liquid crystal WGM mode,including trypsin(concentration range of 0.75~2.00μg·mL^(-1)),pH(4.55~6.86),and DNA(concentration range of 90~490μg·mL^(-1)).Experimental results demonstrate that using the proposed method and three principles for

关 键 词：液晶 回音壁模式 光谱标定 Savitzky-Golay滤波 

分 类 号：O433.1[机械工程—光学工程]