@ARTICLE{Pacewicz_Adam_Terahertz_2023,
 author={Pacewicz, Adam and Kopyt, Paweł and Cuper, Jerzy and Krysicki, Mateusz and Salski, Bartłomiej},
 volume={31},
 number={2},
 journal={Opto-Electronics Review},
 pages={e144596},
 howpublished={online},
 year={2023},
 publisher={Polish Academy of Sciences (under the auspices of the Committee on Electronics and Telecommunication) and Association of Polish Electrical Engineers in cooperation with Military University of Technology},
 abstract={An innovative measurement setup for the dielectric characterisation of fibres in a terahertz time-domain spectrometer using an HDPE elliptical lens for coupling into the fibres has been built and validated by measurements of several different types of samples. The setup is based on a commercial all fibre-coupled terahertz time-domain spectrometer. Measurements of the effective refractive index have been conducted on polypropylene-based three-dimensional printing filaments, silica glass rods, and a polytetrafluoroethylene cord of lowered density, covering the frequency range of approximately 100 GHz to 1 THz. The theoretical part of the work includes numerical calculations performed via the finite difference eigenmode method and the characteristic equations of a uniform circular dielectric waveguide for a few guided modes, from which it is clear that primarily the fundamental mode propagates along the fibre. Details on model-based phase corrections, crucial to the accurate determination of the effective refractive index of dispersive fibres, have been presented as well.},
 type={Article},
 title={Terahertz dielectric characterisation of fibres in a time-domain spectrometer},
 URL={http://journals.pan.pl/Content/126873/PDF/OPELRE_2023_31_2_A_Pacewicz.pdf},
 doi={10.24425/opelre.2023.144596},
 keywords={terahertz spectroscopy, fibre characterisation, dielectric materials},
}