石英管增强拉曼光纤探头粉末样品探测

Quartz tube enhanced Raman fiber probe for powder detection

拉曼光谱技术以其多组分同时探测、分子指纹特性等优点被广泛应用于多个领域,但其较低探测灵敏度严重限制了此技术的进一步发展。为了提高拉曼光谱技术粉末样品原位分析能力,提出了一种基于石英管增强的高灵敏度拉曼光纤探头。探头采取内镀金属空芯光纤用于光信号的传输,有效减小了背景信号对拉曼光谱的影响;探头底端采用石英管设计,增大采样体积和收集效率,提高了拉曼光谱的探测灵敏度。理论分析了石英管拉曼光谱技术可提高粉末样品的探测灵敏度,详细介绍了探头的设计和实现,进一步评估探头的性能,结果表明:相较于球透镜拉曼探头,拉曼信号强度(NaHCO_(3))增强2.92倍。为模拟实际应用场景,采用光纤拉曼探头成功获得了容器中不同深度粉末样品(Na_(2)SO_(4)和NaHCO_(3))的拉曼光谱信息。文中设计的石英管增强拉曼探头具有外径尺寸小(外径仅为2mm)、灵敏度高等优点,可对深层次粉末样品进行探测,为现场粉末样品原位分析提供了一种新途径。

Raman spectroscopy has been widely used in many fields due to its advantages of multi-component simultaneous detection and molecular fingerprinting characteristics,but its low detection sensitivity severely limits the further development.In order to improve the in-situ analysis capability of powder samples by Raman spectroscopy,a high-sensitivity optical fiber Raman probe based on quartz tube enhancement is proposed.The metal-coated hollow-core fiber is used for optical signal transmission,which effectively reduces the influence of background signal on Raman spectrum.The bottom of the probe is designed with a quartz tube,which increases the sampling volume and collection efficiency,it improves the detection sensitivity of Raman spectrum.Firstly,theoretical analysis of quartz tube Raman spectroscopy can improve the detection sensitivity of powder samples.Secondly,the design and implementation of the probe are introduced in detail.Lastly,the performance of the probe is further evaluated.The results show that the Raman signal intensity(NaHCO_(3))increased by a factor of 2.92 compared with the spherical lens Raman probe.In order to simulate practical application scenarios,the Raman spectral information of powder samples(Na_(2)SO_(4)and NaHCO_(3))at different depths in the container is successfully obtained by using the fiber Raman probe.The quartz tube-enhanced Raman probe designed in this paper has the advantages of small outer diameter(only 2mm)and high sensitivity.It can detect deep powder samples and provide a new way for in-situ analysis of powder samples on site.