Chemical recognition in terahertz time-domain spectroscopy and imaging
Open accessAbstract
In this paper, we present an overview of chemical recognition with ultrashort THz pulses. We describe the experimental technique and demonstrate how signals for chemical recognition of substances in sealed containers can be obtained, based on the broadband absorption spectra of the substances. We then discuss chemical recognition in combination with THz imaging and show that certain groups of biological substances may give rise to characteristic recognition signals. Finally, we explore the power of numerical prediction of absorption spectra of molecular crystals and illuminate some of the challenges facing state-of-the-art computational chemistry software.
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α-lactose has resonant frequencies at 0.53, 1.2, and 1.4 THz.
“We prepared sample disks made from α-lactose monohydrate powders (Spectrum Chemical Mfg. Corp., Gardena, CA, USA) with resonant frequencies at 0.53, 1.2, and 1.4 THz [50,51].”
From Translation-Invariant Zero-Phase Wavelet Methods for Feature Extraction in Terahertz Time-Domain Spectroscopy (2022) · cites this paper as [50]
Section 2 (Chemical sensitivity; page not available) identifies the sample as α-lactose monohydrate and reports distinct features in its THz absorption spectrum. Section 3 (Chemical recognition in terahertz imaging; page not available) also describes prominent lactose spectral features, but our copy does not give the claimed resonance frequencies of 0.53, 1.2, and 1.4 THz. (LLM, conf=0.84)
Experimental — accuracy not yet measuredThe systematic error from an approximated transfer function can be completely removed from the optical constants if a nonapproximation technique for material parameter extraction is employed.
“Furthermore, it can be completely removed from the optical constants if a nonapproximation technique for material parameter extraction, such as that given in [2,22,23], is employed.”
From Uncertainty in terahertz time-domain spectroscopy measurement (2008) · cites this paper as [22]
Section 2 (Chemical sensitivity; page not available in our copy) gives a field-ratio equation used to obtain absorption and refractive index. It does not describe a nonapproximation extraction technique or say that such a technique completely removes systematic error from an approximated transfer function. Searches for those terms and for exact extraction methods found no passage addressing that claim. (LLM, conf=0.72)
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References 25 · Cited by 288
- Authors
- Fischer, B., Hoffmann, M., Helm, H., Modjesch, G., & Jepsen, P. U.
- Affiliations
- University of Freiburg (DE)
- Venue
- Semiconductor Science and Technology
- Publisher
- IOP Publishing
- Published
- 2005-06-08
- Volume
- 20
- Issue
- 7
- Pages
- S246-S253
- ISSN
- 0268-1242 (ISSN-L)
- 1361-6641
- OpenAlex
- W2166378898
- Semantic Scholar
- d98b9a4a526731820993be4b40cbcd83c5698986
- Cited by
- 288
- References
- 25
- Citations by year
- 2026: 8 · 2025: 13 · 2024: 9 · 2023: 12 · 2022: 17 · 2021: 18 · 2020: 13 · 2019: 19 · 2018: 24 · 2017: 13 · 2016: 13 · 2015: 9 · 2014: 14 · 2013: 7 · 2012: 15
- FWCI
- 16.15
- Type
- journal article
- Language
- en
- Open access
- bronze
- doi.org
- Locations
- Semiconductor Science and Technology (publishedVersion)
- Adelaide Research & Scholarship (AR&S) (University of Adelaide) (submittedVersion)
- FreiDok plus (Universitätsbibliothek Freiburg) (submittedVersion)
- Funders
- Bundesministerium für Bildung und Forschung
- Topics
- Physical Sciences › Engineering › Electrical and Electronic Engineering › Terahertz technology and applications
- Physical Sciences › Chemistry › Spectroscopy › Spectroscopy and Laser Applications
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Biophysics › Spectroscopy Techniques in Biomedical and Chemical Research
- Keywords
- chemical recognition, terahertz time-domain spectroscopy, terahertz imaging, sealed containers, biological substances, molecular crystals, computational chemistry software
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