Abstract-Application of a robotic THz imaging system for sub-surface analysis of ancient human remains

Eva-Maria Stübling, Arno Rehn, Tabea Siebrecht, Yannick Bauckhage, Lena Öhrström, Patrick Eppenberger, Jan C. Balzer, Frank Rühli, Martin Koch,

https://www.nature.com/articles/s41598-019-40211-7

We used a robotic-based THz imaging system to investigate the sub-surface structure of an artificially mummified ancient Egyptian human left hand. The results obtained are compared to the results of a conventional CT and a micro-CT scan. Using such a robotic THz system promises new insights into the sub-surface structure of human remains. The depth resolution of the THz images exceeds the resolution of a conventional CT scan and is comparable with a micro-CT scan. The advantage of THz measurements over micro-CT scans is the fact that even comparatively large samples, like complete bodies, can be scanned. These would not fit into a conventional micro-CT scanner.

Abstract-Terahertz quasi time-domain spectroscopy based on telecom technology for 1550 nm

Robert B. Kohlhaas, Arno Rehn, Simon Nellen, Martin Koch, Martin Schell, Roman J. B. Dietz, and Jan C. Balzer

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-25-11-12851

We present a fiber-coupled terahertz quasi time-domain spectroscopy system driven by a laser with a central wavelength of 1550 nm. By using a commercially available multimode laser diode in combination with state-of-the-art continuous wave antennas, a bandwidth of more than 1.8 THz is achieved. The peak signal-to-noise ratio is around 60 dB. A simulation based on the optical spectrum of the laser diode and the transfer function of the THz path is in agreement with the experimental results. The system is used to extract the refractive index from two different samples and the results indicate that the performance is up to 1.8 THz comparable to a terahertz time-domain spectroscopy system.

© 2017 Optical Society of America

Abstract-Periodic sampling errors in terahertz time-domain measurements

Arno Rehn, David Jahn, Jan. C. Balzer, and Martin Koch

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-25-6-6712

An extensive investigation of the origin and the impact of periodic sampling errors of terahertz time-domain spectroscopy systems is given. We present experimental findings and compare them to a theoretical model which is developed in this work. Special attention is given to the influence on the extraction of the refractive index from measurements. It can be shown that even distortions of the spectrum at frequencies higher than the used bandwidth can have a significant impact on the extracted refractive index.

© 2017 Optical Society of America