Reflection-absorption infrared spectroscopy of thin films using an external cavity quantum cascade laser

Mark C. Phillips, Ian M. Craig, Thomas A. Blake

Research output: Chapter in Book/Report/Conference proceedingConference contribution

7 Scopus citations


We present experimental demonstrations using a broadly tunable external cavity quantum cascade laser (ECQCL) to perform Reflection-Absorption InfraRed Spectroscopy (RAIRS) of thin layers and residues on surfaces. The ECQCL compliance voltage was used to measure fluctuations in the ECQCL output power and improve the performance of the RAIRS measurements. Absorption spectra from self-assembled monolayers of a fluorinated alkane thiol and a thiol carboxylic acid were measured and compared with FTIR measurements. RAIRS spectra of the explosive compounds PETN, RDX, and tetryl deposited on gold substrates were also measured. Rapid measurement times and low noise were demonstrated, with <1E-3 absorbance noise for a 10 second measurement time.

Original languageEnglish (US)
Title of host publicationQuantum Sensing and Nanophotonic Devices X
StatePublished - 2013
Externally publishedYes
EventQuantum Sensing and Nanophotonic Devices X - San Francisco, CA, United States
Duration: Feb 3 2013Feb 7 2013

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


OtherQuantum Sensing and Nanophotonic Devices X
Country/TerritoryUnited States
CitySan Francisco, CA


  • Infrared spectroscopy
  • complex refractive index
  • explosives detection
  • quantum cascade laser
  • tunable laser

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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