Towards simultaneous calibration-free and ultra-fast sensing of temperature and species in the intrapulse mode

Robin Chrystie, Ehson Fawad Nasir, Aamir Farooq

Research output: Contribution to journalArticlepeer-review

26 Scopus citations

Abstract

We report on exploiting the down-chirp phenomenon seen in quantum cascade lasers (QCLs), when modulated with long pulses, for the purpose of performing calibration-free and temporally resolved measurements. Intrapulse spectra of a native species (e.g., H2O), common to combustion environments, were generated near λ = 7.62 μm at repetition rates as high as 3.125 MHz. Two-line absorption spectroscopy was employed to infer calibration-free temperature from the chirp-induced intrapulse spectra. In this study, such temperature measurements were limited to rates of 250 kHz due to spectral distortion at higher repetition rates. We demonstrate the ease at which accurate temperatures and H2O compositions can be achieved using simple and compact QCLs operated in the intrapulse mode. The sensor is also applicable to other species, and has the potential to be integrated into commercial technologies. © 2014 The Combustion Institute.
Original languageEnglish (US)
Pages (from-to)3757-3764
Number of pages8
JournalProceedings of the Combustion Institute
Volume35
Issue number3
DOIs
StatePublished - Jul 2 2014

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Mechanical Engineering
  • Physical and Theoretical Chemistry

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