Fabry–Perot Effect Suppression in Gas Cells Used in THz Absorption Spectrometers. Experimental Verification

A standard measuring gas cell used in absorption spectrometers is a cylinder enclosed by two transparent windows. The Fabry–Perot effects caused by multiple reflections of terahertz waves between these windows produce significant variations in the transmitted radiation intensity. Therefore, the Fabr...

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Main Authors: George K. Raspopin, Alexey V. Borisov, Arnaud Cuisset, Francis Hindle, Semyon V. Yakovlev, Yury V. Kistenev
Format: Article
Language:English
Published: MDPI AG 2024-11-01
Series:Sensors
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Online Access:https://www.mdpi.com/1424-8220/24/22/7380
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author George K. Raspopin
Alexey V. Borisov
Arnaud Cuisset
Francis Hindle
Semyon V. Yakovlev
Yury V. Kistenev
author_facet George K. Raspopin
Alexey V. Borisov
Arnaud Cuisset
Francis Hindle
Semyon V. Yakovlev
Yury V. Kistenev
author_sort George K. Raspopin
collection DOAJ
description A standard measuring gas cell used in absorption spectrometers is a cylinder enclosed by two transparent windows. The Fabry–Perot effects caused by multiple reflections of terahertz waves between these windows produce significant variations in the transmitted radiation intensity. Therefore, the Fabry–Perot effects should be taken into account to correctly measure absorption spectra in Bouguer law-based absorption spectroscopy. One approach to reducing the Fabry–Perot effects is based on inserting an additional external movable window with the standard measuring gas cell. This was proposed and numerically analyzed in our previous work. This paper is aimed at the experimental validation of this method when using amplitude modulation (AM) spectroscopy. Also, a comparison of the efficiency of reducing the Fabry–Perot effects using this method is experimentally compared to frequency modulation spectroscopy. The latter was shown to effectively reduce the Fabry–Perot effects compared to AM spectroscopy with the standard measuring gas cell, and the use of the external movable window was shown to further improve the elimination of Fabry–Perot effects.
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spelling doaj-art-ba8708ee45bb4e7db4c4f22ededa5d482025-08-20T02:04:41ZengMDPI AGSensors1424-82202024-11-012422738010.3390/s24227380Fabry–Perot Effect Suppression in Gas Cells Used in THz Absorption Spectrometers. Experimental VerificationGeorge K. Raspopin0Alexey V. Borisov1Arnaud Cuisset2Francis Hindle3Semyon V. Yakovlev4Yury V. Kistenev5Laboratory of the Molecular Imaging and Machine Learning, Tomsk State University, 634050 Tomsk, RussiaLaboratory of the Molecular Imaging and Machine Learning, Tomsk State University, 634050 Tomsk, RussiaLaboratoire de Physico Chimie de l’Atmosphère, Université du Littoral Côte d’Opale, 59140 Dunkirk, FranceLaboratoire de Physico Chimie de l’Atmosphère, Université du Littoral Côte d’Opale, 59140 Dunkirk, FranceV.E. Zuev Institute of Atmospheric Optics Russian Academy of Sciences, Siberian Branch, 634055 Tomsk, RussiaLaboratory of the Molecular Imaging and Machine Learning, Tomsk State University, 634050 Tomsk, RussiaA standard measuring gas cell used in absorption spectrometers is a cylinder enclosed by two transparent windows. The Fabry–Perot effects caused by multiple reflections of terahertz waves between these windows produce significant variations in the transmitted radiation intensity. Therefore, the Fabry–Perot effects should be taken into account to correctly measure absorption spectra in Bouguer law-based absorption spectroscopy. One approach to reducing the Fabry–Perot effects is based on inserting an additional external movable window with the standard measuring gas cell. This was proposed and numerically analyzed in our previous work. This paper is aimed at the experimental validation of this method when using amplitude modulation (AM) spectroscopy. Also, a comparison of the efficiency of reducing the Fabry–Perot effects using this method is experimentally compared to frequency modulation spectroscopy. The latter was shown to effectively reduce the Fabry–Perot effects compared to AM spectroscopy with the standard measuring gas cell, and the use of the external movable window was shown to further improve the elimination of Fabry–Perot effects.https://www.mdpi.com/1424-8220/24/22/7380amplitude modulation spectroscopyFabry–Perot effectsfrequency modulation spectroscopyterahertz gas absorption spectroscopy
spellingShingle George K. Raspopin
Alexey V. Borisov
Arnaud Cuisset
Francis Hindle
Semyon V. Yakovlev
Yury V. Kistenev
Fabry–Perot Effect Suppression in Gas Cells Used in THz Absorption Spectrometers. Experimental Verification
Sensors
amplitude modulation spectroscopy
Fabry–Perot effects
frequency modulation spectroscopy
terahertz gas absorption spectroscopy
title Fabry–Perot Effect Suppression in Gas Cells Used in THz Absorption Spectrometers. Experimental Verification
title_full Fabry–Perot Effect Suppression in Gas Cells Used in THz Absorption Spectrometers. Experimental Verification
title_fullStr Fabry–Perot Effect Suppression in Gas Cells Used in THz Absorption Spectrometers. Experimental Verification
title_full_unstemmed Fabry–Perot Effect Suppression in Gas Cells Used in THz Absorption Spectrometers. Experimental Verification
title_short Fabry–Perot Effect Suppression in Gas Cells Used in THz Absorption Spectrometers. Experimental Verification
title_sort fabry perot effect suppression in gas cells used in thz absorption spectrometers experimental verification
topic amplitude modulation spectroscopy
Fabry–Perot effects
frequency modulation spectroscopy
terahertz gas absorption spectroscopy
url https://www.mdpi.com/1424-8220/24/22/7380
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