Mid-infrared(MIR)spectrometers are invaluable tools for molecular fingerprinting and hyper-spectral imaging.Among the available spectroscopic approaches,GHz MIR dual-comb absorption spectrometers have the potential to...Mid-infrared(MIR)spectrometers are invaluable tools for molecular fingerprinting and hyper-spectral imaging.Among the available spectroscopic approaches,GHz MIR dual-comb absorption spectrometers have the potential to simultaneously combine the high-speed,high spectral resolution,and broad optical bandwidth needed to accurately study complex,transient events in chemistry,combustion,and microscopy.However,such a spectrometer has not yet been demonstrated due to the lack of GHz MIR frequency combs with broad and full spectral coverage.Here,we introduce the first broadband MIR frequency comb laser platform at 1 GHz repetition rate that achieves spectral coverage from 3 to 13 μm.This frequency comb is based on a commercially available 1.56 μm mode-locked laser,robust all-fiber Er amplifiers and intra-pulse difference frequency generation(IP-DFG)of few-cycle pulses in x(2)nonlinear crystals.When used in a dual comb spectroscopy(DCS)configuration,this source will simultaneously enable measurements with μs time resolution,1 GHz(0.03 cm-1)spectral point spacing and a full bandwidth of>5 THz(>166 cm-1)anywhere within the MIR atmospheric windows.This represents a unique spectroscopic resource for characterizing fast and non-repetitive events that are currently inaccessible with other sources.展开更多
Mid-infrared frequency-comb spectroscopy enables measurement of molecules at megahertz spectral resolution,sub-hertz frequency accuracy,and microsecond acquisition speed.However,the widespread adoption of this techniq...Mid-infrared frequency-comb spectroscopy enables measurement of molecules at megahertz spectral resolution,sub-hertz frequency accuracy,and microsecond acquisition speed.However,the widespread adoption of this technique has been hindered by the complexity and alignment sensitivity of mid-infrared frequency-comb sources.Leveraging the underexplored mid-infrared window of silica fibers presents a promising approach to address these challenges.In this study,we present the first,to the best of our knowledge,experimental demonstration and quantitative numerical description of mid-infrared frequency-comb generation in silica fibers.Our all-silica-fiber frequency comb spans over two octaves(0.8μm to 3.4μm)with a power output of 100 mW in the mid-infrared region.The amplified quantum noise is suppressed using four-cycle(25 fs)driving pulses,with the carrier-envelope offset frequency exhibiting a signal-to-noise ratio of 40 dB and a free-running bandwidth of 90 kHz.Our developed model provides quantitative guidelines for mid-infrared frequency-comb generation in silica fibers,enabling all-fiber frequency-comb spectroscopy in diverse fields such as organic synthesis,pharmacokinetics processes,and environmental monitoring.展开更多
基金Thanks to NSF 2019195,Defense Advanced Research Project Agency(W31P4Q-15-1-0011)AirForceOffceof ScientificResearch(FA9550-20-1-0328and FA9550-16-1-0016)NISTfor fundingas wellas Daniel Herman,Kristina Chang,Franklyn Quinlan and lan.Coddington for their contributions and comments on this manuscript.We thank P.Schunemann and K.Zawilski at BAE forprovidingtheCSPandOP-GaPcrystals.
文摘Mid-infrared(MIR)spectrometers are invaluable tools for molecular fingerprinting and hyper-spectral imaging.Among the available spectroscopic approaches,GHz MIR dual-comb absorption spectrometers have the potential to simultaneously combine the high-speed,high spectral resolution,and broad optical bandwidth needed to accurately study complex,transient events in chemistry,combustion,and microscopy.However,such a spectrometer has not yet been demonstrated due to the lack of GHz MIR frequency combs with broad and full spectral coverage.Here,we introduce the first broadband MIR frequency comb laser platform at 1 GHz repetition rate that achieves spectral coverage from 3 to 13 μm.This frequency comb is based on a commercially available 1.56 μm mode-locked laser,robust all-fiber Er amplifiers and intra-pulse difference frequency generation(IP-DFG)of few-cycle pulses in x(2)nonlinear crystals.When used in a dual comb spectroscopy(DCS)configuration,this source will simultaneously enable measurements with μs time resolution,1 GHz(0.03 cm-1)spectral point spacing and a full bandwidth of>5 THz(>166 cm-1)anywhere within the MIR atmospheric windows.This represents a unique spectroscopic resource for characterizing fast and non-repetitive events that are currently inaccessible with other sources.
基金The Science and Technology Commission of Shanghai MunicipalityShenzhen Science and Technology Program(2023A1515012285)+4 种基金Strategic Priority Research Program of the Chinese Academy of Sciences(XDB35030101)Fundamental Research Funds for the Central Universities(23GH030508)Mathematical Basic Science Research Project of Shaanxi(22JSQ039)NaturalScience Basic Research Program of Shaanxi Province(2023-JCYB-502)National Natural Science Foundation of China(62275236,62305270)。
文摘Mid-infrared frequency-comb spectroscopy enables measurement of molecules at megahertz spectral resolution,sub-hertz frequency accuracy,and microsecond acquisition speed.However,the widespread adoption of this technique has been hindered by the complexity and alignment sensitivity of mid-infrared frequency-comb sources.Leveraging the underexplored mid-infrared window of silica fibers presents a promising approach to address these challenges.In this study,we present the first,to the best of our knowledge,experimental demonstration and quantitative numerical description of mid-infrared frequency-comb generation in silica fibers.Our all-silica-fiber frequency comb spans over two octaves(0.8μm to 3.4μm)with a power output of 100 mW in the mid-infrared region.The amplified quantum noise is suppressed using four-cycle(25 fs)driving pulses,with the carrier-envelope offset frequency exhibiting a signal-to-noise ratio of 40 dB and a free-running bandwidth of 90 kHz.Our developed model provides quantitative guidelines for mid-infrared frequency-comb generation in silica fibers,enabling all-fiber frequency-comb spectroscopy in diverse fields such as organic synthesis,pharmacokinetics processes,and environmental monitoring.
