Picture of neon light reading 'Open'

Discover open research at Strathprints as part of International Open Access Week!

23-29 October 2017 is International Open Access Week. The Strathprints institutional repository is a digital archive of Open Access research outputs, all produced by University of Strathclyde researchers.

Explore recent world leading Open Access research content this Open Access Week from across Strathclyde's many research active faculties: Engineering, Science, Humanities, Arts & Social Sciences and Strathclyde Business School.

Explore all Strathclyde Open Access research outputs...

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

Bain, James R. P. and Lengden, Michael and Stewart, George and Johnstone, Walter (2016) Recovery of absolute absorption line shapes in tunable diode laser spectroscopy using external amplitude modulation with balanced detection. IEEE Sensors Journal, 16 (3). pp. 675-680. ISSN 1530-437X

[img]
Preview
Text (Bain-etal-Sensors-2015-Recovery-of-absolute-absorption-line-shapes-in-tunable-diode-laser-spectroscopy-using-external-amplitude)
Bain_etal_Sensors_2015_Recovery_of_absolute_absorption_line_shapes_in_tunable_diode_laser_spectroscopy_using_external_amplitude.pdf - Accepted Author Manuscript

Download (343kB) | Preview

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.