Abstract-A Low-Loss Terahertz Fiber With Crossed Rectangular Shaped Dielectric Strips

Zhu, Y.-F. ; School of Physics and Communication Electronics, Jiangxi Normal University & Key Laboratory of Optoelectronic and Telecommunication, Nanchang, P. R. China ; Chen, M.-Y. ; Wang, H.

http://ieeexplore.ieee.org/xpl/articleDetails.jsp?reload=true&arnumber=7156175&filter%3DAND%28p_IS_Number%3A5741778%29

We present a design and investigation of a low-loss terahertz fiber consisting of crossed rectangular shaped dielectric strips and a supporting outer cladding. The core-guided mode can be effectively confined in the fiber core with a large portion of mode power distributed in air holes adjacent to the solid material, which results in a low absorption loss property of the fiber. Low dispersion transmission can be obtained due to the thinner dielectric strips. In addition, a high birefringence on a level of $10 ^{-2}$over a wide frequency range can be obtained by simply adopting crossed dielectric strips with different thicknesses.

Abstract-Doped polymer for low-loss dielectric material in the terahertz range

Daniel Headland, Peter Thurgood, Daniel Stavrevski, Withawat Withayachumnankul, Derek Abbott, Madhu Bhaskaran, and Sharath Sriram
https://www.osapublishing.org/ome/abstract.cfm?uri=ome-5-6-1373

The dielectric properties of an elastomeric polymer are modified with the inclusion of dopants, with the aim of reducing dielectric loss in the terahertz range. Polydimethylsiloxane (PDMS) is selected as the host polymer, and micro/nano-particle powders of either alumina or polytetrafluoroethylene (PTFE) are employed as dopants. Composite samples are prepared, and characterised with terahertz time-domain spectroscopy (THz-TDS). The samples exhibit significantly reduced dielectric loss, with a maximum reduction of 15.3% in loss tangent reported for a sample that is 40% PTFE by mass. Results are found to have reasonable agreement with the Lichtenecker logarithmic mixture formula, and any deviation can be accounted for by agglomeration of dopant micro/nano-particles. The new dielectric composites are promising for devising efficient micro-structure components at terahertz frequencies.

© 2015 Optical Society of America

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Abstract-Anisotropic terahertz dielectric responses of sodium nitrate crystal

Xiaojian Fu,   Youting Song,   Chang Qing Sun and   Ji Zhou  

Phys. Chem. Chem. Phys., 2014, Accepted Manuscript

DOI: 10.1039/C3CP55484H
Received 28 Dec 2013, Accepted 18 Feb 2014
First published online 18 Feb 2014
http://pubs.rsc.org/en/content/articlelanding/2014/cp/c3cp55484h#!divAbstract

Terahertz (THz) spectroscopy has become an effective tool to characterize the low-frequency rotational and vibrational modes of molecules. In addition, novel THz dielectric responses and optical properties on the basis of molecular rotation and vibration have attracted lots of attention because of their potential application in THz devices. In this paper, the dielectric response of low-symmetric sodium nitrate crystal in the frequency range of 0.2-1.5 THz was experimentally demonstrated. Four absorption bands at 0.23, 0.47, 0.92, and 1.15 THz were observed in the dielectric spectra and were tentatively ascribed to the rotational motion of nitrate ions. Based on the molecular rotation mechanism, the dielectric anisotropy and dielectric resonance of the crystal were discussed in detail.