光纤倏逝波型石英增强光声光谱技术
Fiber evanescent wave quartz-enhanced photoacoustic spectroscopy
摘要
Abstract
In a conventional system of quartz-enhanced photoacoustic spectroscopy (QEPAS), the size of block-like optical collimation focusing lens group is difficult to reduce, and the structural stability is poor, which makes it hard to adapt itself to some special conditions, such as narrow space and vibrating circumstance. Based on this situation, in this research the fiber evanescent wave technique is combined with QEPAS. Therefore, trace gas detection for acetylene (C2H2) based on an all-fiber structural QEPAS system is developed. To obtain the characteristics of fiber evanescent wave, the optical distribution of micro structural fiber is simulated and the evanescent wave power ratio is calculated based on the COMSOL Multiphysics software. In order to increase the QEPAS 2f signal amplitude, the optical path between fiber taper and quartz tuning fork(QTF)and the laser wavelength modulation depth are optimized. In addition, two kinds of QTFs with different resonant frequencies are optimized. Finally,a QTF with a lower resonant frequency of 30.720 kHz is adopted as the acoustic wave transducer, and a minimum detection limit (MDL) of 6.25×10?4(volume fraction)is obtained with a laser wavelength modulation depth of 0.24 cm?1. To investigate the evanescent wave power of micro structural fiber, the fiber taper diameter is measured by a scanning electron microscope. Subsequently, by combining the diameter of fiber taper with the theoretical calculation results, we determine an evanescent wave power of 455.9 μW, and the normalization of noise equivalent absorption (NNEA) which indicates the sensor sensitivity is 4.18×10?7cm?1·W·Hz?1/2.关键词
痕量气体检测/石英增强光声光谱/光纤倏逝波Key words
trace gas detection/quartz-enhanced photoacoustic spectroscopy/fiber evanescent wave引用本文复制引用
何应,马欲飞,佟瑶,彭振芳,于欣..光纤倏逝波型石英增强光声光谱技术[J].物理学报,2018,67(2):26-33,8.基金项目
国家自然科学基金(批准号:61505041)、黑龙江省自然科学基金(批准号:F2015011)、中国博士后科学基金特别资助(批准号:2015T80350)、中国博士后科学基金面上项目(批准号:2014M560262)、黑龙江省博士后科学基金(批准号:LBH-Z14074, LBH-TZ0507)、中央高校基本科研业务费专项资金、哈尔滨市应用技术研究与开发项目(批准号:2016RAQXJ140)和国家重大科学仪器设备开发专项(批准号:2012YQ040164)资助的课题. Project supported by the National Natural Science Foundation of China(Grant No. 61505041),the Natural Science Foun-dation of Heilongjiang Province of China(Grant No. F2015011),the Special Financial Grant from the China Postdoctoral Science Foundation (Grant No. 2015T80350), the General Financial Grant from the China Postdoctoral Science Foun-dation (Grant No. 2014M560262), the Postdoctoral Fund of Heilongjiang Province, China (Grant Nos. LBH-Z14074, LBH-TZ0507), the Fundamental Research Funds for the Central Universities, the Application Technology Research and Development Projects of Harbin, China (Grant No. 2016RAQXJ140), and the National Key Scientific Instrument and Equipment Development Projects of China (Grant No. 2012YQ040164). （批准号:61505041）
