Article

Applied Physics B

, Volume 82, Issue 4, pp 649-654

Quantum cascade laser-based carbon monoxide detection on a second time scale from human breath

  • B.W.M. MoeskopsAffiliated withDepartment of Molecular and Laser Physics, Institute for Molecules and Materials, Radboud University Nijmegen Email author 
  • , H. NausAffiliated withDepartment of Molecular and Laser Physics, Institute for Molecules and Materials, Radboud University Nijmegen
  • , S.M. CristescuAffiliated withDepartment of Molecular and Laser Physics, Institute for Molecules and Materials, Radboud University Nijmegen
  • , F.J.M. HarrenAffiliated withDepartment of Molecular and Laser Physics, Institute for Molecules and Materials, Radboud University Nijmegen

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Abstract

We present three different detection schemes for measuring carbon monoxide (CO) in direct absorption using a thermoelectrically cooled, distributed-feedback pulsed quantum cascade (qc) laser operating between 2176 and 2183 cm-1. The laser emission has overlap with the strong R(8)1 ro-vibrational transition in CO at 2176.2835 cm-1. Firstly, by utilizing the frequency chirp of the qc-laser with long laser pulses, a minimal detectable absorption of 1.2×10-5 cm-1 is achieved at an acquisition rate of 3 Hz. Additionally, with short laser pulses and slow frequency scanning a minimal detectable absorption 8.2×10-7 cm-1 is reported, with an acquisition time of 60 s. Finally, a novel amplitude modulation technique is developed to facilitate real-time measurement of CO in exhaled air. The application of this detector to detection of CO in a single breath as a potential non-invasive diagnostic tool is shown.