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Diffuse terahertz spectroscopy in turbid media using a wavelet-based bimodality spectral analysis
Current terahertz (THz) spectroscopy techniques only use the coherent light beam for spectral imaging. In the presence of electromagnetic scattering, however, the scattering-mitigated incoherent beams allow for flexible emitter-detector geometries, which enable applications such as seeing through tu...
Autores principales: | , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Nature Publishing Group UK
2021
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8611087/ https://www.ncbi.nlm.nih.gov/pubmed/34815438 http://dx.doi.org/10.1038/s41598-021-02068-7 |
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author | Khani, Mahmoud E. Osman, Omar B. Arbab, M. Hassan |
author_facet | Khani, Mahmoud E. Osman, Omar B. Arbab, M. Hassan |
author_sort | Khani, Mahmoud E. |
collection | PubMed |
description | Current terahertz (THz) spectroscopy techniques only use the coherent light beam for spectral imaging. In the presence of electromagnetic scattering, however, the scattering-mitigated incoherent beams allow for flexible emitter-detector geometries, which enable applications such as seeing through turbid media. Despite this potential, THz spectroscopy using diffuse waves has not been demonstrated. The main obstacles are the very poor signal to noise ratios of the diffused fields and the resonance-like spectral artifacts due to multiple Mie scattering events that obscure the material absorption signatures. In this work, we demonstrate diffuse THz spectroscopy of a heterogeneous sample through turbid media using a novel technique based on the wavelet multiresolution analysis and the bimodality coefficient spectrum, which we define here for the first time using the skewness and kurtosis of the spectral images. The proposed method yields broadband and simultaneous material characterization at detection angles as high as 90° with respect to the incident beam. We determined the accuracy of the wavelet-based diffuse spectroscopy at oblique detection angles, by evaluating the area under the receiver operating characteristic curves, to be higher than 95%. This technique is agnostic to any a priori information on the spectral signatures of the sample materials or the characteristics of the scattering medium, and can be expanded for other broadband spectroscopic modalities. |
format | Online Article Text |
id | pubmed-8611087 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2021 |
publisher | Nature Publishing Group UK |
record_format | MEDLINE/PubMed |
spelling | pubmed-86110872021-11-26 Diffuse terahertz spectroscopy in turbid media using a wavelet-based bimodality spectral analysis Khani, Mahmoud E. Osman, Omar B. Arbab, M. Hassan Sci Rep Article Current terahertz (THz) spectroscopy techniques only use the coherent light beam for spectral imaging. In the presence of electromagnetic scattering, however, the scattering-mitigated incoherent beams allow for flexible emitter-detector geometries, which enable applications such as seeing through turbid media. Despite this potential, THz spectroscopy using diffuse waves has not been demonstrated. The main obstacles are the very poor signal to noise ratios of the diffused fields and the resonance-like spectral artifacts due to multiple Mie scattering events that obscure the material absorption signatures. In this work, we demonstrate diffuse THz spectroscopy of a heterogeneous sample through turbid media using a novel technique based on the wavelet multiresolution analysis and the bimodality coefficient spectrum, which we define here for the first time using the skewness and kurtosis of the spectral images. The proposed method yields broadband and simultaneous material characterization at detection angles as high as 90° with respect to the incident beam. We determined the accuracy of the wavelet-based diffuse spectroscopy at oblique detection angles, by evaluating the area under the receiver operating characteristic curves, to be higher than 95%. This technique is agnostic to any a priori information on the spectral signatures of the sample materials or the characteristics of the scattering medium, and can be expanded for other broadband spectroscopic modalities. Nature Publishing Group UK 2021-11-23 /pmc/articles/PMC8611087/ /pubmed/34815438 http://dx.doi.org/10.1038/s41598-021-02068-7 Text en © The Author(s) 2021 https://creativecommons.org/licenses/by/4.0/Open AccessThis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) . |
spellingShingle | Article Khani, Mahmoud E. Osman, Omar B. Arbab, M. Hassan Diffuse terahertz spectroscopy in turbid media using a wavelet-based bimodality spectral analysis |
title | Diffuse terahertz spectroscopy in turbid media using a wavelet-based bimodality spectral analysis |
title_full | Diffuse terahertz spectroscopy in turbid media using a wavelet-based bimodality spectral analysis |
title_fullStr | Diffuse terahertz spectroscopy in turbid media using a wavelet-based bimodality spectral analysis |
title_full_unstemmed | Diffuse terahertz spectroscopy in turbid media using a wavelet-based bimodality spectral analysis |
title_short | Diffuse terahertz spectroscopy in turbid media using a wavelet-based bimodality spectral analysis |
title_sort | diffuse terahertz spectroscopy in turbid media using a wavelet-based bimodality spectral analysis |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8611087/ https://www.ncbi.nlm.nih.gov/pubmed/34815438 http://dx.doi.org/10.1038/s41598-021-02068-7 |
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