基于二次曲线拟合的共焦拉曼光谱探测方法

Confocal Raman Spectroscopy Method Based on Quadratic Curve Fitting

拉曼光谱技术因其光谱信息丰富、非接触、无破坏、样品用量少、高灵敏度等特点,为现代前沿基础科研领域提供一种有力的分析手段,成为分析科学的研究热点。激光共焦拉曼技术结合共焦显微探测和拉曼光谱探测技术,具有空间分辨力高、可层析探测的优势,在物理化学、材料科学、生物医学、考古及文物鉴定、刑侦科学等众多领域应用广泛。现有共焦拉曼系统由于在扫描过程中无法对探测点进行定焦,因而在长时间的探测过程中会因环境变化、系统漂移等问题导致系统离焦,从而造成测量结果存在误差甚至错误的问题。本文针对这一问题,在现有共焦拉曼系统的基础上,提出一种基于二次曲线拟合的共焦拉曼光谱探测方法。该方法利用二次曲线对光谱共焦曲线进行拟合,通过寻找曲线最大值,得到系统焦点,进而在扫描过程中对每个探测点进行焦点定位后,采集该点光谱信息,从而保证扫描过程中系统始终位于焦点位置,消除系统离焦对实验结果的影响,实现共焦拉曼光谱系统的精确测量。通过仿真分析和实验结果表明:本文提出的基于二次曲线拟合的共焦拉曼光谱探测方法可以有效消除系统离焦对实验结果造成的影响,提高系统轴向定焦的准确度,为共焦拉曼光谱技术的进一步应用提供了保证,是一种行之有效的定焦准确、抗漂移强的拉曼光谱测量方法。

Raman spectroscopy plays an improtant role in analytical science because of its unique characteristics,such as non-contact and non-destructive detecting,fewer sample consumption,high sensitivity and other characteristics,and it provides a powerful analytical tool for the modern basic research fields.Because of the combination of confocal microscopy technology and Raman spectroscopy technology,confocal Raman microscopy has the advantage of both high resolution spectroscopy and chromatography detection,which inherits from confocal microscopy and raman spectroscopy.As a result,it is widely used in many fields,such as physical chemistry,materials science,biomedical,archaeological,cultural identification,and forensic science.But with the environmental changing,the system drifting or other issues,during the long detection process,the system turns to defocusing.As a result,during the hole scanning process,the system can not be focused on every detection point,and then it would lead to a mistake.Eventurally,conventional confocal Raman system could obtain the presence of measurement error even erroneous results in the long process.In this paper,on the basis of conventional confocal Raman system,a confocal Raman spectroscopy method based on quadratic curve fitting is proposed to solve this problem.Based on the principle that the maxium of the concal curve corresponding the system foucs,the steps to find system foucus as follows：fist,usesing quadratic curve to fit confocal curve;second,finding the maxium of the confocal curve;and last obtaining the system foucs.With this method,during the scanning process,every point should be focused,therefore,the effect of defocusing is eliminated efficiently,and accurate measurements of confocal Raman spectroscopy system is achieved.Through simulation and experimental results show that：the proposed method that confocal Raman spectroscopy method based on quadratic curve fitting can effectively eliminate the influence of system defocus on experimental result,and effectively improve the axial system of fixed focus accuracy,which could provide a guarantee for further application of confocal Raman spectroscopy.This anti-drift method is effective and accurate in focusing with great potential to be applied in broader areas.