Recovery of absolute absorption line shapes in tunable diode laser spectroscopy using external amplitude modulation with balanced detection

James R. P. Bain, Michael Lengden, George Stewart, Walter Johnstone

Research output: Contribution to journalArticle

7 Citations (Scopus)
197 Downloads (Pure)

Abstract

Accurate recovery of an absorption lineshape is important in many industrial applications for simultaneous measurement of gas concentration and pressure or temperature. Here we demonstrate a method, based on a modification to the Hobbs balanced receiver circuit, for background signal nulling when external amplitude modulation of the laser output is used. Compared with direct or non-nulled detection techniques, we demonstrate that the method significantly improves the signal to noise ratio to a level comparable to that of conventional second harmonic wavelength modulation spectroscopy. Most importantly, normalisation and recovery of the lineshape is straightforward and immune to the difficulties that afflict lineshape recovery with conventional wavelength modulation spectroscopy.
Original languageEnglish
Pages (from-to)675-680
Number of pages6
JournalIEEE Sensors Journal
Volume16
Issue number3
Early online date12 Oct 2015
DOIs
Publication statusPublished - 1 Feb 2016

Keywords

  • balance detection
  • absorption line shape recovery
  • gas sensors
  • diode laser spectroscopy
  • optical fibers

Fingerprint Dive into the research topics of 'Recovery of absolute absorption line shapes in tunable diode laser spectroscopy using external amplitude modulation with balanced detection'. Together they form a unique fingerprint.

Cite this