High-Speed Mid-Infrared Frequency Modulation Spectroscopy Based on Quantum Cascade Laser

Chen Peng, Gang Chen, Jianping Tang, Lijun Wang, Zhongquan Wen, Haijun Zhou, Rainer Martini

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

We demonstrated a high-speed mid-infrared frequency modulation spectroscopy scheme based on a distributed-feedback quantum Cascade laser for the application in trace gas sensing by means of all-optical frequency modulation. With this method, the modulation frequency spectrum of a gas sample can be obtained within the mid-infrared pulse duration of ∼ 200 ns. A frequency modulation of the middle infrared lasing optical frequency was achieved in quantum Cascade laser with a modulation frequency of 200 MHz by illuminating with a 1550-nm near-infrared laser. For CO gas, with 2-mW near-infrared illumination, the noise-equivalent sensitivity of the frequency modulation spectroscopy was estimated to be 0.12 ppmv for an absorption length of 6.1 m, indicating an improvement by a factor of 7 compared with Voigt-fitted direct absorption spectroscopy (0.84 ppmv). The frequency modulation signal was found to be proportional to the incident near-infrared power, and therefore, the noise-equivalent sensitivity is expected to be further improved by increasing the near-infrared illumination power. This high-speed frequency modulation spectroscopy based on the distributed-feedback quantum Cascade laser has promising applications in high-speed and high-sensitivity gas sensing.

Original languageEnglish
Article number7452592
Pages (from-to)1727-1730
Number of pages4
JournalIEEE Photonics Technology Letters
Volume28
Issue number16
DOIs
StatePublished - 15 Aug 2016

Keywords

  • Frequency modulation spectroscopy
  • gas sensing
  • middle-infrared spectroscopy
  • quantum cascade laser

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