Microscale fiber photoacoustic spectroscopy for in situ and real-time trace gas sensing  

作　　者：Jun Ma Enbo Fan Haojie Liu Yi Zhang Cong Mai Xin Li Wei Jin Bai-Ou Guan 

机构地区：[1]Jinan University,Institute of Photonics Technology,Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications,Guangzhou,China [2]Jinan University,College of Physics&Optoelectronic Engineering,Guangzhou,China [3]Jinan University,College of Life Science and Technology,Guangzhou,China [4]Guangdong Provincial People’s Hospital,Southern Medical University,Guangdong Academy of Medical Sciences,Department of Critical Care Medicine,Guangzhou,China [5]The Hong Kong Polytechnic University,Department of Electrical and Electronic Engineering,Hong Kong,China

出　　处：《Advanced Photonics》2024年第6期119-132,共14页先进光子学(英文)

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.62275106 and 62135006);the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(Grant No.2019BT02X105);the Natural Science Foundation of Guangdong Province(Grant Nos.2022A1515010105 and 2023A1515011415);the Doctoral Students Top Innovative Talent Training Program of Jinan University(Grant No.2023CXB016).

摘　　要：Miniaturized laser spectroscopy capable of in situ and real-time ppb-level trace gas sensing is of fundamental importance for numerous applications,including environment monitoring,industry process control,and biomedical diagnosis.Benchtop laser spectroscopy systems based on direct absorption,photoacoustic,and Raman effects exhibit high sensitivity but face challenges for in situ and real-time gas sensing due to their bulky size,slow response,and offline sampling.We demonstrate a microscale highperformance all-fiber photoacoustic spectrometer integrating the key components,i.e.,the photoacoustic gas cell and the optical microphone,into a single optical fiber tip with a diameter of 125μm.Without a long optical path to enhance the light–gas interaction,the fiber-tip gas cell with acoustic-hard boundary tightly confines and amplifies the local photoacoustic wave,compensating for the sensitivity loss during miniaturization.This localized acoustic wave is demodulated by high-sensitivity fiber-optic interferometry,enabling a∼9 ppb detection limit for acetylene gas approaching the benchtop system.The microscale fiber spectrometer also exhibits a short response time of∼18 ms and a subnanoliter sample volume,not only suitable for routine realtime in situ trace gas measurement but also inspiring new applications such as two-dimensional gas flow concentration mapping and in vivo intravascular blood gas monitoring as showcased.

关 键 词：optical fiber sensors photoacoustic spectroscopy acoustic sensing trace gas detection 

分 类 号：TN253[电子电信—物理电子学] TH744.1[机械工程—光学工程]