Abstract

Infrared spectroscopy is commonly applied to the analysis of small gas-phase molecules. One of the limitations of using Fourier transform infrared (FT-IR) spectroscopy for these applications is the time response of long path length gas cells. Hollow waveguides (HW) that transmit in the mid-infrared spectral range have higher optical efficiencies compared to long path length cells due to smaller cell volumes. This study characterizes a silver coated, 2 mm inner diameter HW for the analysis of carbon monoxide (CO) and nitric oxide (NO) and compares the performance to a 3 m gas cell and traditional gas analyzers. The HW was found to have a CO response time less than the NDIR analyzer and approximately one-tenth of the response time on the FT-IR system equipped with a 3 m gas cell. The utility of the increased response time was demonstrated by measuring CO concentrations in sidestream cigarette smoke at the same temporal resolution as an NDIR analyzer. A 10 to 60% increase in sensitivity using various frequencies for both CO and NO was observed using the HW compared to the 3 m multipass gas cell. However, cost savings for gas-sensing applications can be achieved on a per analyte basis by using FT-IR spectroscopy, especially in combination with a HW gas-sensing module, which is significantly less expensive than a multipass gas cell.

Low-level and ultralow-volume hollow waveguide based carbon monoxide sensor

Jia Chen, Andreas Hangauer, Rainer Strzoda, Maximilian Fleischer, and Markus-Christian Amann
Opt. Lett. 35(21) 3577-3579 (2010)

ICL-based TDLAS sensor for real-time breath gas analysis of carbon monoxide isotopes

Ramin Ghorbani and Florian M. Schmidt
Opt. Express 25(11) 12743-12752 (2017)

Low-volume, fast response-time hollow silica waveguide gas cells for mid-IR spectroscopy

Daniel Francis, Jane Hodgkinson, Beth Livingstone, Paul Black, and Ralph P. Tatam
Appl. Opt. 55(25) 6797-6806 (2016)

Performance of a fire detector based on a compact laser spectroscopic carbon monoxide sensor

A. Hangauer, J. Chen, R. Strzoda, M. Fleischer, and M.-C. Amann
Opt. Express 22(11) 13680-13690 (2014)

Mid-infrared quantum cascade laser based off-axis integrated cavity output spectroscopy for biogenic nitric oxide detection

Yury A. Bakhirkin, Anatoliy A. Kosterev, Chad Roller, Robert F. Curl, and Frank K. Tittel
Appl. Opt. 43(11) 2257-2266 (2004)