scholarly journals Mail Inspection Based on Terahertz Time-Domain Spectroscopy

2021 ◽  
Vol 11 (3) ◽  
pp. 950
Author(s):  
Daniel Molter ◽  
Daniel Hübsch ◽  
Thorsten Sprenger ◽  
Korbinian Hens ◽  
Konstantinos Nalpantidis ◽  
...  
Keyword(s):  
Data Analysis ◽  
Spectral Range ◽  
Time Domain ◽  
Spectral Investigation ◽  
Machine Design ◽  
Terahertz Waves ◽  
Terahertz Time Domain Spectroscopy ◽  
Time Domain Spectroscopy

One of the most prominent applications of terahertz time-domain spectroscopy is the spectral investigation of materials covered by visibly opaque objects. Therefore, terahertz waves are well suited to inspect the content of mail. We report on our work on mail inspection in this spectral range including machine design, optical layouts, data analysis, and implementations.

Investigation of Dielectric Properties of Polymers and their Discrimination Using Terahertz Time-Domain Spectroscopy with Principal Component Analysis

2016 ◽  
Vol 71 (3) ◽  
pp. 456-462 ◽  
Author(s):  
Muhammad Mumtaz ◽  
Ahsan Mahmood ◽  
Sabih D. Khan ◽  
M. Aslam Zia ◽  
Mushtaq Ahmed ◽  
...  
Keyword(s):  
Spectral Range ◽  
Time Domain ◽  
Principal Component ◽  
Component Analysis ◽  
Thz Radiation ◽  
Terahertz Time Domain Spectroscopy ◽  
Time Domain Spectroscopy ◽  
Styrene Acrylonitrile ◽  
Characteristic Features ◽  
First Time

Polymers are among the most commonly used materials in our everyday life. They are generally transparent to terahertz (THz) radiation, but are quite difficult to differentiate using optical techniques as few or no characteristic features exist in the spectral range of <2.0 THz for small and portable radiation systems. In this work, we report experimental measurement of refractive indices and absorption coefficients of styrene acrylonitrile (SAN) and Bakelite in the spectral range of 0.2–2.0 THz for the first time. Additionally, we demonstrate that by combining principle component analysis (PCA) with THz time-domain spectroscopy one can differentiate such polymers. In this analysis, the first three principle components PC1, PC2, and PC3 depict >94% variance with a distribution of 72.45%, 11.52%, and 9.38%, respectively.

Grating-assisted coupling of terahertz waves into a dielectric waveguide studied by terahertz time-domain spectroscopy

2002 ◽  
Vol 41 (30) ◽  
pp. 6507 ◽  
Author(s):  
Jean-François Roux ◽  
Fabien Aquistapace ◽  
Frédéric Garet ◽  
Lionel Duvillaret ◽  
Jean-Louis Coutaz
Keyword(s):  
Time Domain ◽  
Dielectric Waveguide ◽  
Terahertz Waves ◽  
Terahertz Time Domain Spectroscopy ◽  
Time Domain Spectroscopy

scholarly journals Terahertz spectroscopy and imaging for gastric cancer diagnosis

2020 ◽  
Author(s):  
Faustino Wahaia ◽  
Irmantas Kašalynas ◽  
Linas Minkevičius ◽  
Catia Carvalho Silva ◽  
Andrzej Urbanowicz ◽  
...  
Keyword(s):  
Time Domain ◽  
Terahertz Spectroscopy ◽  
Human Cancer ◽  
Terahertz Waves ◽  
Terahertz Time Domain Spectroscopy ◽  
Tissue Samples ◽  
Time Domain Spectroscopy ◽  
Affected Tissue ◽  
Gastrointestinal Tissue ◽  
Thz Absorption

Terahertz waves are sensitive to differences in biological tissue hydration, we present promising results regarding the feasibility of applying this with terahertz time-domain spectroscopy and imaging for early detection of cancer through the characterisation of human gastrointestinal tissue with cancer-affected regions. To do that, healthy (normal) and carcinoma-affected gastric tissue samples at different stages were measured using transmission terahertz time-domain spectroscopy in the frequency range of 0.15–2.00 THz. Absorption coefficients and refractive index spectra of both normal and carcinoma-affected tissue were extracted and analysed. The results confirm that the techniques may be powerful tools to perform qualitative, early diagnosis of human cancer.

scholarly journals Improving a Terahertz Time-Domain Spectroscopy Apparatus Using Neodymium Magnets

2015 ◽  
Vol 62 ◽  
pp. 10-14
Author(s):  
Kaori Yano ◽  
Toshiaki Hattori
Keyword(s):  
Time Domain ◽  
Signal To Noise Ratio ◽  
Laser Pulses ◽  
Terahertz Wave ◽  
Femtosecond Laser Pulses ◽  
Terahertz Waves ◽  
Terahertz Time Domain Spectroscopy ◽  
Wave Source ◽  
Time Domain Spectroscopy ◽  
Neodymium Magnets

The signal-to-noise ratio obtained from terahertz time-domain spectroscopy is significantly affected by the low available power of terahertz waves. We constructed a terahertz-wave source with emission power enhanced by a magnetic field. The emitter is composed of an InAs wafer and two neodymium magnets. The emitter was irradiated by femtosecond laser pulses. The data quality of terahertz spectroscopic measurements was evaluated, and reduction of error in the data obtained due to the terahertz power enhancement was observed.

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