Panpan Sun: Key Laboratory of Advanced Manufacturing for Optical Systems (CAS), Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China.
Mengpeng Hu: Key Laboratory of Advanced Manufacturing for Optical Systems (CAS), Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China.
Licai Zhu: University of Chinese Academy of Sciences, Beijing 100049, China.
Hui Zhang: Key Laboratory of Advanced Manufacturing for Optical Systems (CAS), Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China.
Jinguang Lv: Key Laboratory of Advanced Manufacturing for Optical Systems (CAS), Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China. ORCID
Yu Liu: Key Laboratory of Advanced Manufacturing for Optical Systems (CAS), Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China.
Jingqiu Liang: Key Laboratory of Advanced Manufacturing for Optical Systems (CAS), Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China.
Qiang Wang: Key Laboratory of Advanced Manufacturing for Optical Systems (CAS), Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China. ORCID
Dissolved gases in the aquatic environment are critical to understanding the population of aquatic organisms and the ocean. Currently, laser absorption techniques based on membrane separation technology have made great strides in dissolved gas detection. However, the prolonged water-gas separation time of permeable membranes remains a key obstacle to the efficiency of dissolved gas analysis. To mitigate these limitations, we demonstrated direct measurement of dissolved gas using the evanescent-wave absorption spectroscopy of a tapered silica micro-fiber. It enhanced the analysis efficiency of dissolved gases without water-gas separation or sample preparation. The feasibility of this sensor for direct measurement of dissolved gases was verified by taking the detection of dissolved ammonia as an example. With a sensing length of 5 mm and a consumption of ~50 µL, this sensor achieves a system response time of ~11 min and a minimum detection limit (MDL) of 0.015%. Possible strategies are discussed for further performance improvement in in-situ applications requiring fast and highly sensitive dissolved gas sensing.
