Wavelength modulated multiheterodyne spectroscopy using Fabry-Pérot quantum cascade lasers

Andreas Hangauer, Jonas Westberg, Eric Zhang, Gerard Wysocki

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


Multiheterodyne spectroscopy implemented with semiconductor Fabry-Pérot lasers is a method for broadband (> 20 cm-1), high spectral resolution (∼1 MHz) and high time resolution (< 1 μs/spectrum) spectroscopy with no moving parts utilizing off-the-shelf laser sources. The laser stabilization approach demonstrated here enables continuous frequency tuning (at 12.5 Hz repetition rate) while allowing for multiheterodyne wavelength modulation spectroscopy (WMS). Spectroscopic detection of N2O around 1185 cm-1 is experimentally realized, which shows a direct absorption sensitivity limit of ∼1.5×10-3/√Hz fractional absorption per mode. This can be lowered using WMS down to 5×10-4/√Hz per mode, limited by optical fringes. This approaches the range of sensitivities of standard single-mode laser based spectrometers, which demonstrates that the multiheterodyne method is well-suited for chemical sensing of spectrally broadened absorption features or for multi-species measurements.

Original languageEnglish (US)
Pages (from-to)25298-25307
Number of pages10
JournalOptics Express
Issue number22
StatePublished - Oct 31 2016

All Science Journal Classification (ASJC) codes

  • Atomic and Molecular Physics, and Optics


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