Polymer microstructured optical fibers for terahertz wave guiding.

We outline the most recent technological advancements in the design, fabrication and characterization of polymer microstructured optical fibers (MOFs) for applications in the terahertz waveband. Focusing on specific experimental demonstrations, we show that polymer optical fibers provide a very flexible route towards THz wave guiding. Crucial incentives include the large variety of the low-cost and relatively low absorption loss polymers, the facile fiber preform fabrication by molding, drilling, stacking and extrusion, and finally, the simple fabrication through fiber drawing at low forming temperatures.

Composite THz materials using aligned metallic and semiconductor microwires, experiments and interpretation.

We report fabrication method and THz characterization of composite films containing either aligned metallic (tin alloy) microwires or chalcogenide As2Se3 microwires. The microwire arrays are made by stack-and-draw fiber fabrication technique using multi-step co-drawing of low-melting-temperature metals or semiconductor glasses together with polymers. Fibers are then stacked together and pressed into composite films.

Spectral characterization of porous dielectric subwavelength THz fibers fabricated using a microstructured molding technique.

We report two novel fabrication techniques, as well as THz spectral transmission and propagation loss measurements of subwavelength plastic wires with highly porous (up to 86%) and non-porous transverse geometries. The two fabrication techniques we describe are based on the microstructured molding approach. In one technique the mold is made completely from silica by stacking and fusing silica capillaries to the bottom of a silica ampoule.

Fabrication and THz loss measurements of porous subwavelength fibers using a directional coupler method.

We report several strategies for the fabrication of porous subwavelength fibers using low density Polyethylene plastic for low-loss terahertz light transmission applications. We also characterize transmission losses of the fabricated fibers in terahertz using a novel non-destructive directional coupler method. Within this method a second fiber is translated along the length of the test fiber to probe the power attenuation of a guided mode.

Fabrication strategies and potential applications of the "green" microstructured optical fibers.

Biodegradable microstructured polymer optical fibers have been created using synthetic biomaterials such as poly(L-lactic acid), poly(epsilon-caprolactone), and cellulose derivatives. Original processing techniques were utilized to fabricate a variety of biofriendly microstructured fibers that hold potential for in vivo light delivery, sensing, and controlled drug-release.

Porous polymer fibers for low-loss Terahertz guiding.

We propose two designs of effectively single mode porous polymer fibers for low-loss guiding of terahertz radiation. First, we present a fiber of several wavelengths in diameter containing an array of sub-wavelength holes separated by sub-wavelength material veins. Second, we detail a large diameter hollow core photonic bandgap Bragg fiber made of solid film layers suspended in air by a network of circular bridges.

Guiding in the visible with "colorful" solid-core Bragg fibers.

We report on the fabrication and characterization of solid-core all-polymer Bragg fibers consisting of a large-diameter polymethyl methylacrylate (PMMA) core surrounded by 50 alternating PMMA/Polystyrene (PS) polymer layers. By modifying the reflector layer thickness we illustrate that bandgap position can be adjusted at will in the visible. Moreover, such fibers are intensely colored in both the transmission and the outside reflection modes.

Prospective for biodegradable microstructured optical fibers.

We report fabrication of a novel microstructured optical fiber made of biodegradable and water soluble materials that features approximately 1 dB/cm transmission loss. Two cellulose butyrate tubes separated with hydroxypropyl cellulose powder were codrawn into a porous double-core fiber offering integration of optical, microfluidic, and potentially drug release functionalities.

Drawing of the hollow all-polymer Bragg fibers.

Drawing of the hollow all-polymer Bragg fibers based on PMMA/PS and PVDF/PC materials combinations are demonstrated. Hole collapse during drawing effects the uniformity of a photonic crystal reflector in the resultant fiber. We first investigate how the core collapse effects fiber transmission properties.

Theory and applications of an alternative lattice Boltzmann grid refinement algorithm.

This contribution proposes an alternative lattice Boltzmann grid refinement algorithm that overcomes the drawbacks that plague existing approaches. We demonstrate that this algorithm is accurate and applicable for all values of the relaxation time. We also show that this algorithm can significantly speed up the flow settlement process.