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Rapid, Time-Division Multiplexed, Direct Absorption- and Wavelength Modulation-Spectroscopy
We present a tunable diode laser spectrometer with a novel, rapid time multiplexed direct absorption- and wavelength modulation-spectroscopy operation mode. The new technique allows enhancing the precision and dynamic range of a tunable diode laser absorption spectrometer without sacrificing accurac...
Autores principales: | , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
MDPI
2014
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4279545/ https://www.ncbi.nlm.nih.gov/pubmed/25405508 http://dx.doi.org/10.3390/s141121497 |
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author | Klein, Alexander Witzel, Oliver Ebert, Volker |
author_facet | Klein, Alexander Witzel, Oliver Ebert, Volker |
author_sort | Klein, Alexander |
collection | PubMed |
description | We present a tunable diode laser spectrometer with a novel, rapid time multiplexed direct absorption- and wavelength modulation-spectroscopy operation mode. The new technique allows enhancing the precision and dynamic range of a tunable diode laser absorption spectrometer without sacrificing accuracy. The spectroscopic technique combines the benefits of absolute concentration measurements using calibration-free direct tunable diode laser absorption spectroscopy (dTDLAS) with the enhanced noise rejection of wavelength modulation spectroscopy (WMS). In this work we demonstrate for the first time a 125 Hz time division multiplexed (TDM-dTDLAS-WMS) spectroscopic scheme by alternating the modulation of a DFB-laser between a triangle-ramp (dTDLAS) and an additional 20 kHz sinusoidal modulation (WMS). The absolute concentration measurement via the dTDLAS-technique allows one to simultaneously calibrate the normalized 2f/1f-signal of the WMS-technique. A dTDLAS/WMS-spectrometer at 1.37 μm for H(2)O detection was built for experimental validation of the multiplexing scheme over a concentration range from 50 to 3000 ppmV (0.1 MPa, 293 K). A precision of 190 ppbV was achieved with an absorption length of 12.7 cm and an averaging time of two seconds. Our results show a five-fold improvement in precision over the entire concentration range and a significantly decreased averaging time of the spectrometer. |
format | Online Article Text |
id | pubmed-4279545 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2014 |
publisher | MDPI |
record_format | MEDLINE/PubMed |
spelling | pubmed-42795452015-01-15 Rapid, Time-Division Multiplexed, Direct Absorption- and Wavelength Modulation-Spectroscopy Klein, Alexander Witzel, Oliver Ebert, Volker Sensors (Basel) Article We present a tunable diode laser spectrometer with a novel, rapid time multiplexed direct absorption- and wavelength modulation-spectroscopy operation mode. The new technique allows enhancing the precision and dynamic range of a tunable diode laser absorption spectrometer without sacrificing accuracy. The spectroscopic technique combines the benefits of absolute concentration measurements using calibration-free direct tunable diode laser absorption spectroscopy (dTDLAS) with the enhanced noise rejection of wavelength modulation spectroscopy (WMS). In this work we demonstrate for the first time a 125 Hz time division multiplexed (TDM-dTDLAS-WMS) spectroscopic scheme by alternating the modulation of a DFB-laser between a triangle-ramp (dTDLAS) and an additional 20 kHz sinusoidal modulation (WMS). The absolute concentration measurement via the dTDLAS-technique allows one to simultaneously calibrate the normalized 2f/1f-signal of the WMS-technique. A dTDLAS/WMS-spectrometer at 1.37 μm for H(2)O detection was built for experimental validation of the multiplexing scheme over a concentration range from 50 to 3000 ppmV (0.1 MPa, 293 K). A precision of 190 ppbV was achieved with an absorption length of 12.7 cm and an averaging time of two seconds. Our results show a five-fold improvement in precision over the entire concentration range and a significantly decreased averaging time of the spectrometer. MDPI 2014-11-14 /pmc/articles/PMC4279545/ /pubmed/25405508 http://dx.doi.org/10.3390/s141121497 Text en © 2014 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution license (http://creativecommons.org/licenses/by/3.0/). |
spellingShingle | Article Klein, Alexander Witzel, Oliver Ebert, Volker Rapid, Time-Division Multiplexed, Direct Absorption- and Wavelength Modulation-Spectroscopy |
title | Rapid, Time-Division Multiplexed, Direct Absorption- and Wavelength Modulation-Spectroscopy |
title_full | Rapid, Time-Division Multiplexed, Direct Absorption- and Wavelength Modulation-Spectroscopy |
title_fullStr | Rapid, Time-Division Multiplexed, Direct Absorption- and Wavelength Modulation-Spectroscopy |
title_full_unstemmed | Rapid, Time-Division Multiplexed, Direct Absorption- and Wavelength Modulation-Spectroscopy |
title_short | Rapid, Time-Division Multiplexed, Direct Absorption- and Wavelength Modulation-Spectroscopy |
title_sort | rapid, time-division multiplexed, direct absorption- and wavelength modulation-spectroscopy |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4279545/ https://www.ncbi.nlm.nih.gov/pubmed/25405508 http://dx.doi.org/10.3390/s141121497 |
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