基于SiPM单光子探测器的荧光光谱仪研究

Fluorescence spectrometer based on SiPM single photon detector

为了解决激光诱导荧光检测系统存在的光学结构复杂、体积大、成本高以及灵敏度不足等主要问题,研制了一种高灵敏、小型化的荧光光谱仪。该光谱仪以349 nm半导体激光器作为激发光源,采用正交型光路,将4×4窄带滤光片阵列与具有单光子灵敏度的硅光电倍增器(SiPM)阵列耦合,可实现光谱信息的多通道探测,具备结构紧凑、成本较低以及稳定性好等优点。以荧光素钠为测试样品,对光谱仪性能进行了评估。实验结果表明,光谱仪的检测限优于5×10^(−11)mol·L^(−1),在5×10^(−11)mol·L^(−1)到1×10^(−9)mol·L^(−1)的溶液浓度范围内,被测溶液浓度与检测所得荧光强度满足良好的线性关系,线性相关系数为0.99839。此外,光谱仪还具备良好的重复性,荧光峰值强度的相对标准偏差小于10%。因此,该光谱仪兼具灵敏度高、线性度好、重复性与可靠性强等优点,可以满足现场实时检测的需求。

In order to solve the main problems of the laser-induced fluorescence detection system,such as complex optical structure,large volume,high cost and insufficient sensitivity,a sensitive and miniaturized fluorescence spectrometer was proposed.The spectrometer used a 349 nm semiconductor laser as the excitation light source,adopted an orthogonal optical path,coupled a 4×4 narrowband filter array and a silicon photomultiplier(SiPM)array with single photon sensitivity,which could realize multi-channel detection of spectral information.It had the advantages of compact structure,low cost and good stability.Sodium fluorescein was used for performance evaluation of the spectrometer.The experimental results show that the detection limit of the spectrometer is better than 5×10^(−11) mol·L^(−1).The linear correlation coefficient of the fluorescence intensity is 0.99839 with the concentration from 5×10^(−11) mol·L^(−1) to 1×10^(−9) mol·L^(−1).In addition,the spectrometer also has good repeatability,and the relative standard deviation of the fluorescence peak intensity is less than 10%.Therefore,the spectrometer has the advantages of high sensitivity,good linearity,strong repeatability and reliability,and can meet the needs of on-site real-time detection.