Diffuse terahertz spectroscopy in turbid media using a wavelet-based bimodality spectral analysis
Abstract 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 t...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Nature Portfolio
2021-11-01
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| Series: | Scientific Reports |
| Online Access: | https://doi.org/10.1038/s41598-021-02068-7 |
| _version_ | 1818695227699888128 |
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| author | Mahmoud E. Khani Omar B. Osman M. Hassan Arbab |
| author_facet | Mahmoud E. Khani Omar B. Osman M. Hassan Arbab |
| author_sort | Mahmoud E. Khani |
| collection | DOAJ |
| description | Abstract 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. |
| first_indexed | 2024-12-17T13:42:08Z |
| format | Article |
| id | doaj.art-ff9b439960094070bc7b0b3492c73b7f |
| institution | Directory Open Access Journal |
| issn | 2045-2322 |
| language | English |
| last_indexed | 2024-12-17T13:42:08Z |
| publishDate | 2021-11-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | Scientific Reports |
| spelling | doaj.art-ff9b439960094070bc7b0b3492c73b7f2022-12-21T21:46:15ZengNature PortfolioScientific Reports2045-23222021-11-0111111310.1038/s41598-021-02068-7Diffuse terahertz spectroscopy in turbid media using a wavelet-based bimodality spectral analysisMahmoud E. Khani0Omar B. Osman1M. Hassan Arbab2Department of Biomedical Engineering, Stony Brook UniversityDepartment of Biomedical Engineering, Stony Brook UniversityDepartment of Biomedical Engineering, Stony Brook UniversityAbstract 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.https://doi.org/10.1038/s41598-021-02068-7 |
| spellingShingle | Mahmoud E. Khani Omar B. Osman M. Hassan Arbab Diffuse terahertz spectroscopy in turbid media using a wavelet-based bimodality spectral analysis Scientific Reports |
| 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 |
| url | https://doi.org/10.1038/s41598-021-02068-7 |
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