Zhen Wang, Qinxue Nie, Haojia Sun, Qiang Wang, Simone Borri, Paolo De Natale, Wei Ren
Author Information
Zhen Wang: Department of Mechanical and Automation Engineering, The Chinese University of Hong Kong, New Territories, Hong Kong SAR, China. wangzhen@link.cuhk.edu.hk. ORCID
Qinxue Nie: Department of Mechanical and Automation Engineering, The Chinese University of Hong Kong, New Territories, Hong Kong SAR, China.
Haojia Sun: Department of Mechanical and Automation Engineering, The Chinese University of Hong Kong, New Territories, Hong Kong SAR, China.
Qiang Wang: State Key Laboratory of Applied Optics, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 130033, Changchun, China. wangqiang@ciomp.ac.cn. ORCID
Simone Borri: CNR-INO-Istituto Nazionale di Ottica, and LENS-European Laboratory for Nonlinear Spectroscopy, 50019, Sesto Fiorentino, Italy. ORCID
Paolo De Natale: CNR-INO-Istituto Nazionale di Ottica, and LENS-European Laboratory for Nonlinear Spectroscopy, 50019, Sesto Fiorentino, Italy.
Wei Ren: Department of Mechanical and Automation Engineering, The Chinese University of Hong Kong, New Territories, Hong Kong SAR, China. renwei@mae.cuhk.edu.hk. ORCID
Photoacoustic dual-comb spectroscopy (DCS), converting spectral information in the optical frequency domain to the audio frequency domain via multi-heterodyne beating, enables background-free spectral measurements with high resolution and broad bandwidth. However, the detection sensitivity remains limited due to the low power of individual comb lines and the lack of broadband acoustic resonators. Here, we develop cavity-enhanced photoacoustic DCS, which overcomes these limitations by using a high-finesse optical cavity for the power amplification of dual-frequency combs and a broadband acoustic resonator with a flat-top frequency response. We demonstrate high-resolution spectroscopic measurements of trace amounts of CH, NH and CO in the entire telecommunications C-band. The method shows a minimum detection limit of 0.6 ppb CH at the measurement time of 100 s, corresponding to the noise equivalent absorption coefficient of 7 × 10cm. The proposed cavity-enhanced photoacoustic DCS may open new avenues for ultrasensitive, high-resolution, and multi-species gas detection with widespread applications.
References
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[PMID: 29714760]
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