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 biomedi...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.展开更多
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)+1 种基金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).
文摘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.
