University of Illinois Urbana-Champaign

High-resolution terahertz gain spectra of mid-infrared pumped NH3

Lampin, Jean-François

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1244864.pptx
3392.pdf

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https://hdl.handle.net/2142/100746

Description

Title
High-resolution terahertz gain spectra of mid-infrared pumped NH3
Author(s)
Lampin, Jean-François
Contributor(s)
  • Postava, Kamil
  • Vanwolleghem, Mathias
  • Margulès, L.
  • Motiyenko, R. A.
  • Pienkina, A.
  • Eliet, Sophie
  • Micica, Martin
Issue Date
2018-06-20
Keyword(s)
Mini-symposium: Far-Infrared Spectroscopy
Date of Ingest
  • 2018-08-17T16:09:40Z
  • 2018-12-12T22:35:20Z
Abstract
Inversion of population in the terahertz (THz) range can be obtained thanks to the optical pumping of polar molecules in the mid-infrared range. Generally it is done with CO2 lasers but recently we have demonstrated the first molecular laser pumped by a quantum cascade laser (QCL). It is based on the optical pumping of the NH3 molecule in the ν2=1 state. The gain is obtained by the stimulated emission on pure inversion transitions of NH3 (large amplitude motions) around 1 THz that are not accessible to continuous-wave (CW) CO2 lasers. We present here CW high-resolution gain measurements of two strong lines: the (3,3) around 1.073 THz and the (4,4) around 1.083 THz. The measurements are done with a THz multiplication chain and an InSb bolometer. The gain profiles are recorded at different pressure and different QCL frequencies as for an IR/THz double resonance experiment. The highest gain at the best conditions are obtained with the (3,3) line: 10 dB/m for a pump power of about 40 mW. To our knowledge this gain is highest measured in the THz range for a CW-pumped molecule. These measurements will help the understanding and the design of our NH3 lasers. This kind of laser will find applications in THz molecular spectroscopy/astronomy as a source or as a local oscillator for heterodyne detection.
Publisher
International Symposium on Molecular Spectroscopy
Type of Resource
text
Genre of Resource
Conference Paper / Presentation
Language
eng
Permalink
http://hdl.handle.net/2142/100746
DOI
10.15278/isms.2018.WI04
Copyright and License Information
Copyright 2018 Jean-François Lampin

Owning Collections

Abstracts & Presentations - 2018 International Symposium on Molecular Spectroscopy PRIMARY