Novel pyroelectric detectors for accurate THz power measurements

2016 ◽  
Vol 83 (6) ◽  
Author(s):  
Andreas Steiger ◽  
Werner Bohmeyer ◽  
Karsten Lange ◽  
Ralf Müller
Keyword(s):  
Spectral Range ◽  
Time Domain ◽  
National Metrology Institute ◽  
Time Domain Spectroscopy ◽  
Thz Detectors ◽  
Pyroelectric Detectors ◽  
Close Cooperation ◽  
Power Measurements ◽  
First Time ◽  
Thz Power

AbstractNovel pyroelectric THz detectors have been developed in close cooperation between PTB, the National Metrology Institute of Germany, and the Sensor- und Lasertechnik company. Covering the broad spectral range from below 50 GHz to beyond 5 THz, these detectors are suited to measure the absolute THz power of time-domain spectroscopy (THz-TDS) systems for the first time.

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.

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.

Applying broadband terahertz time-domain spectroscopy to the analysis of crystalline proteins: a dehydration study

2010 ◽  
Vol 44 (1) ◽  
pp. 129-133 ◽  
Author(s):  
Katarzyna M. Tych ◽  
Andrew D. Burnett ◽  
Christopher D. Wood ◽  
John E. Cunningham ◽  
Arwen R. Pearson ◽  
...  
Keyword(s):  
Time Domain ◽  
Hen Egg White Lysozyme ◽  
Terahertz Time Domain Spectroscopy ◽  
Time Domain Spectroscopy ◽  
Egg White Lysozyme ◽  
Macromolecular Protein ◽  
Hen Egg White ◽  
Long Range Ordering ◽  
First Time ◽  
Lysozyme Crystals

The application of terahertz time-domain spectroscopy and imaging to the study of proteins in crystalline form is demonstrated. Terahertz time-domain spectroscopy is particularly sensitive to the long-range ordering of molecules, with proven utility for the spectroscopy of crystalline biological small molecules. Here, the terahertz time-domain absorption response of a macromolecular protein single crystal is investigated for the first time. In particular, the effect of dehydration on the terahertz absorption coefficient of tetragonal hen egg white lysozyme crystals is reported.

scholarly journals International System of Units (SI) Traceable Noise-Equivalent Power and Responsivity Characterization of Continuous Wave ErAs:InGaAs Photoconductive Terahertz Detectors

Photonics ◽  
2019 ◽  
Vol 6 (1) ◽  
pp. 15 ◽  
Author(s):  
Anuar Fernandez Olvera ◽  
Axel Roggenbuck ◽  
Katja Dutzi ◽  
Nico Vieweg ◽  
Hong Lu ◽  
...  
Keyword(s):  
Continuous Wave ◽  
International System ◽  
Noise Equivalent Power ◽  
National Metrology Institute ◽  
International System Of Units ◽  
System Of Units ◽  
Experimental Values ◽  
Power Measurements ◽  
Thz Power

A theoretical model for the responsivity and noise-equivalent power (NEP) of photoconductive antennas (PCAs) as coherent, homodyne THz detectors is presented. The model is validated by comparison to experimental values obtained for two ErAs:InGaAs PCAs. The responsivity and NEP were obtained from the measured rectified current, the current noise floor in the PCAs, and the incoming THz power for the same conditions. Since the THz power measurements are performed with a pyroelectric detector calibrated by the National Metrology Institute of Germany (PTB), the experimentally obtained values are directly traceable to the International System of Units (SI) for the described conditions. The agreement between the presented model and the experimental results is excellent using only one fitting parameter. A very low NEP of 1.8 fW/Hz at 188.8 GHz is obtained at room temperature.

scholarly journals The Application of Terahertz Time-Domain Spectroscopy to Identification of Potato Late Blight and Fusariosis

Pathogens ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 1336
Author(s):  
Nikita V. Penkov ◽  
Mikhail V. Goltyaev ◽  
Maxim E. Astashev ◽  
Dmitry A. Serov ◽  
Maxim N. Moskovskiy ◽  
...  
Keyword(s):  
Late Blight ◽  
Time Domain ◽  
Spectral Characteristics ◽  
Potato Tubers ◽  
Terahertz Time Domain Spectroscopy ◽  
Time Domain Spectroscopy ◽  
New Methods ◽  
Focus Of Infection ◽  
First Time

Fusarium and late blight (fungal diseases of cereals and potatoes) are among the main causes of crop loss worldwide. A key element of success in the fight against phytopathogens is the timely identification of infected plants and seeds. That is why the development of new methods for identifying phytopathogens is a priority for agriculture. The terahertz time-domain spectroscopy (THz-TDS) is a promising method for assessing the quality of materials. For the first time, we used THz-TDS for assessing the infection of seeds of cereals (oats, wheat and barley) with fusarium and potato tubers of different varieties (Nadezhda and Meteor) with late blight. We evaluated the refractive index, absorption coefficient and complex dielectric permittivity in healthy and infected plants. The presence of phytopathogens on seeds was confirmed by microscopy and PCR. It is shown, that Late blight significantly affected all the studied spectral characteristics. The nature of the changes depended on the variety of the analyzed plants and the localization of the analyzed tissue relative to the focus of infection. Fusarium also significantly affected all the studied spectral characteristics. It was found that THz-TDS method allows you to clearly establish the presence or absence of a phytopathogens, in the case of late blight, to assess the degree and depth of damage to plant tissues.

Sign in / Sign up

Export Citation Format

Share Document