%0 Journal Article %T Transportable mid-infrared laser heterodyne radiometer operating in the shot-noise dominated regime %+ Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères (LERMA (UMR_8112)) %A Shen, Fengjiao %A Wang, Gaoxuan %A Wang, Jingjing %A Tan, Tu %A Wang, Guishi %A Jeseck, Pascal %A Te, Yao-Veng %A Gao, Xiaoming %A Chen, Weidong %< avec comité de lecture %@ 0146-9592 %J Optics Letters %I Optical Society of America - OSA Publishing %V 46 %N 13 %P 3171 %8 2021 %D 2021 %R 10.1364/OL.426432 %Z Physics [physics]Journal articles %X A transportable laser heterodyne radiometer (LHR) based on an external cavity quantum cascade laser, operating in the mid-infrared (mid-IR) around 8 µm, was developed for ground-based remote sensing of multiple greenhouse gases. A newly available novel flexible mid-IR polycrystalline fiber was first exploited to couple solar radiation, real-time captured using a portable sun-tracker, to the LHR receiver. Compared to free space coupling of sunlight, the technique usually used nowadays in the mid-IR, such fiber coupling configuration makes the LHR system readily more stable, simpler, and robust. Operation of the LHR with quasi-shot-noise limited performance was analyzed and experimentally achieved by optimizing local oscillator power. To the best of our knowledge, no such performance approaching the fundamental limit has been reported for a transportable LHR operating at a long mid-IR wavelength around 8 µm. C H 4 and N 2 O were simultaneously measured in the atmospheric column using the developed mid-IR LHR. The experimental LHR spectrum of C H 4 and N 2 O was compared and is in good agreement with a referenced Fourier-transform infrared spectrum from the Total Carbon Column Observing Network observation site and with a simulation spectrum from atmospheric transmission modeling. %G English %L hal-03954248 %U https://hal-cnrs.archives-ouvertes.fr/hal-03954248 %~ OBSPM %~ INSU %~ CNRS %~ UNIV-CERGY %~ LERMA %~ PSL %~ SORBONNE-UNIVERSITE %~ SORBONNE-UNIV %~ SU-SCIENCES %~ OBSPM-PSL %~ ALLIANCE-SU