Abstract-Low-loss polarization-maintaining THz photonic crystal fiber with a triple-hole core

Zhiqing Wu, Xiaoyan Zhou, Handing Xia, Zhaohua Shi, Jin Huang, Xiaodong Jiang, and Weidong Wu

https://www.osapublishing.org/ao/abstract.cfm?uri=ao-56-8-2288&origin=search

In this paper, we report a novel low-loss and polarization-maintaining terahertz (THz) photonic crystal fiber with a triple-hole unit inside the core. The properties of birefringence, effective material loss, confinement loss, bending loss, power fraction, dispersion, and single-mode condition are analyzed in detail by using the finite element methods. Simulation results show that high birefringence at a level of 10−2${10}^{-2}$ can be achieved by simply reducing the diameter of one air hole of the triple-hole core. And low effective material loss down to 30% of its bulk material loss can be achieved in our interested band around 3 THz, due to the high core porosity of the designed triple-hole core. Moreover, this design dramatically facilitates the fabrication process, because of the typical hexagonal structure with all circular air holes and avoiding the troublesome multiple sub-wavelength air holes in the core area. The results reveal that this proposal has potential for efficient THz transmission and other functional applications.

© 2017 Optical Society of America

Abstract-The Special Polarization Characteristic Features of a Three-Dimensional Terahertz Photonic Crystal with a Silicon Inverse Diamond Structure

Chikara Sakurai

(Submitted on 24 Mar 2017)

https://arxiv.org/abs/1703.08297

The band structure of a Si inverse diamond structure whose lattice point shape was vacant regular octahedrons was calculated using plane wave expansion method and a complete photonic band gap was theoretically confirmed at around 0.4 THz. It is said that three-dimensional photonic crystals have no polarization anisotropy in photonic band gap (stop gap, stop band) of high symmetry points in normal incidence. However, it was experimentally confirmed that the polarization orientation of a reflected light was different from that of a incident light, {I(X,Y)}, where (X,Y) is the coordinate system fixed in the photonic crystal. It was studied on a plane (001) at around X point's photonic band gap (0.36 - 0.44 THz) for incident light direction [001] ({\Gamma}-X direction) by rotating a sample in the plane (001), relatively. The polarization orientation of the reflected light was parallel to that of the incident light for the incident polarization orientation I(1,1), I(1,-1). In contrast, the former was perpendicular to the latter for the incident polarization orientation I(1,0), I(0,-1) in the vicinity of 0.38 THz. As far as the photonic crystal in this work is concerned, method of resolution and synthesis of the incident polarization vector isn't apparently able to apply to the analysis of experimental results.

Abstract-Direct Writing of Flexible Barium Titanate/Polydimethylsiloxane 3D Photonic Crystals with Mechanically Tunable Terahertz Properties

http://onlinelibrary.wiley.com/doi/10.1002/adom.201600977/full

Mechanically flexible 3D terahertz photonic crystals (3D-TPCs) are created by the direct-writing technology with a composite ink system composed of polydimethylsiloxane (PDMS) and barium titanate (BaTiO3) nanoparticles. The direct-writing technology allows an easy creation of complex 3D structures with designed geometry, while the refractive indices of the composite ink can be modulated by varying the content of BaTiO3 nanoparticles. Thus, 3D-TPCs with different terahertz properties are obtained by the direct-writing technology. More interestingly, these 3D-TPCs demonstrate a unique tunable terahertz property under external force field due to their mechanical flexibility from the PDMS matrix of the composite ink. Thus, their terahertz property is responsive to external force fields reversibly, which can find novel applications in terahertz technology and other related technological applications