Hollow polycarbonate waveguide with inner Cu coatings for delivery of terahertz radiation

Rutgers, The State University of New Jersey, Нью-Брансуик, New Jersey, United States
Optics Express (Impact Factor: 3.49). 11/2004; 12(21):5263-8. DOI: 10.1364/OPEX.12.005263
Source: PubMed


Terahertz (THz) radiation has important applications in spectroscopy, imaging, and space science. Fiber optics for the THz region have been limited to rigid hollow metallic waveguides or short lengths of solid-core transparent dielectrics such as sapphire and plastic. We have fabricated flexible, hollow polycarbonate waveguides with interior Cu coatings for broadband THz transmission using simple liquid-phase chemistry techniques. The losses for these hollow-core guides were measured using a tunable, cw single-mode far IR laser. The losses for the best guides were found to be less than four dB/m and the single mode of the laser was preserved for the smaller bore waveguides.

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    • "Several waveguide geometries have been demonstrated at terahertz frequencies, including metal wires [14], parallel plate transmission lines [15], hollow polycarbonate waveguides [16] and corrugated metallic surfaces [17]. At terahertz frequencies, most metals behave as a perfect electrical conductor, which does not support a bound plasmonic mode at a planar interface. "
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    New Journal of Physics 08/2013; 15(8):085031. DOI:10.1088/1367-2630/15/8/085031 · 3.56 Impact Factor
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    • "With this nanoparticle layer deposition (NLD) method, an even deposition of NP is possible without the threat of damaging the thin struts of the fiber. Possible fields of applications include surface-enhanced raman spectroscopy (SERS) [4] and surface-enhanced fluorescence , which use the field enhancement near the particle surface [5], refractive index measurement, biomolecule detection [6], or THz waveguiding [7], respectively. Metal NP are under investigation in LSPR sensors as transducers for signal transfers. "
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    ABSTRACT: For fully integrated next-generation plasmonic devices, microstructured optical fibers (MOFs) represent a promising platform technology. This paper describes the use of a dynamic technique to demonstrate the wet chemical deposition of gold and silver nanoparticles (NPs) within MOFs. The plasmonic structures were realized on the internal capillary walls of a three-hole suspended core fiber. Electron micrographs, taken of the inside of the fiber holes, confirm the even distribution of the NP in the MOF over a length of up to 6 m. Accordingly, this procedure is highly productive and makes the resulting MOF-based sensors potentially (very) cost efficient. In proof-of-principle experiments with liquids of different refractive indices, the dependence of the localized surface plasmon resonance (LSPR) on the surroundings was confirmed. Comparing Raman spectra of MOFs with and without NP layers, each one filled with crystal violet, a significant signal enhancement demonstrates the usability of such functionalized MOFs for surface-enhanced Raman spectroscopy (SERS) experiments.
    IEEE Sensors Journal 02/2012; 12(1-12):218 - 224. DOI:10.1109/JSEN.2011.2144580 · 1.76 Impact Factor
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    • "The more commonly used TE mode contains both the tangential and the normal components near the metallic surface. This mode exhibits intermediate loss figures: in a 3 mm bore copper waveguide we measured loss of 3.9 dB/m at 1.89 THz [6]. It is important to realize that minimizing losses in hollow core THz waveguides inevitably leads to designs where the core is much larger than the wavelength. "
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    ABSTRACT: Research on reducing material absorption in Tera-hertz (THz) waveguides has lead to development of guiding struc-tures with transmission losses as low as 1 dB/m. Among waveg-uides that exhibit low loss at THz frequencies are the dielectric-lined hollow cylindrical metallic waveguides. Loss reduction in this waveguide is attributed to an ideal profile of the dominant hybrid HE mode. This mode profile also results in relatively low dis-persion and very high coupling efficiency. In this contribution we overview properties of dielectric-lined hollow cylindrical metallic waveguides for THz waves, their design principles and the fabri-cation process. The impact of the mode profile on losses and dis-persion at THz frequencies is confirmed experimentally by THz near-field imaging and THz time-domain spectroscopy and numer-ically by the finite element method.
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