Multiplexed absorption tomography with calibration-free wavelength modulation spectroscopy

• Published in: Applied physics letters Vol. 104; no. 15
• Main Authors: Cai, Weiwei, Kaminski, Clemens F.
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 14-04-2014
• Subjects: ABSORPTION; ABSORPTION SPECTROSCOPY; Applied physics; Calibration; Combustion; CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; Environment models; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; Multiplexing; SEMICONDUCTOR LASERS; Spectrum analysis; TOMOGRAPHY; Wavelength modulation
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.4871976

We propose a multiplexed absorption tomography technique, which uses calibration-free wavelength modulation spectroscopy with tunable semiconductor lasers for the simultaneous imaging of temperature and species concentration in harsh combustion environments. Compared with the commonly used direct absorption spectroscopy (DAS) counterpart, the present variant enjoys better signal-to-noise ratios and requires no baseline fitting, a particularly desirable feature for high-pressure applications, where adjacent absorption features overlap and interfere severely. We present proof-of-concept numerical demonstrations of the technique using realistic phantom models of harsh combustion environments and prove that the proposed techniques outperform currently available tomography techniques based on DAS.