Note: Stacked rings for terahertz wave-guiding

We demonstrate the construction of corrugated waveguides using stacked rings to propagate terahertz frequencies. The waveguide allows propagation of the same fundamental mode as an optical-fiber, namely, the HE11 mode. This simple concept opens the way for corrugated wave-guides up to several terahertz, maintaining beam characteristics as for terahertz applications. (C) 2011 American Institute of Physics. [doi:10.1063/1.3597579

THz signal transmission in a compact modular waveguide system

The transmission properties of a compact circular corrugated waveguide system are investigated experimentally in the WM-380 band from 500 to 750 GHz. Up to 700 GHz, the average transmission losses range from undetectable to 3.4 dB/m, which is more than four orders of magnitude lower than in rectangular waveguides. The propagation of the lowest-loss HE11 mode is found to be dominant, and long-term measurements of phase and amplitude demonstrate high transmission stabilit

Universal polarizer at 140 for DNP-enhanced NMR experiments

By shining mm-waves upon a sample containing unpaired electron spins, DNP provides a way to enhance NMR signals. We report the characterization of a universal polarizer for EM-waves at 140 GHz made by rectangular grooved mirrors as well as design considerations for optimizing the coupling of a millimeter wave Gaussian beam to DNP/NMR samples. © 2011 IEEE

THz-waves channeling in a monolithic saddle-coil for Dynamic Nuclear Polarization enhanced NMR

A saddle coil manufactured by electric discharge machining (EDM) from a solid piece of copper has recently been realized at EPFL for Dynamic Nuclear Polarization enhanced Nuclear Magnetic Resonance experiments (DNP-NMR) at 9.4 T. The corresponding electromagnetic behavior of radio-frequency (400 MHz) and THz (263 GHz) waves were studied by numerical simulation in various measurement configurations. Moreover, we present an experimental method by which the results of the THz-wave numerical modeling are validated. On the basis of the good agreement between numerical and experimental results, we conducted by numerical simulation a systematic analysis on the influence of the coil geometry and of the sample properties on the THz-wave field, which is crucial in view of the optimization of DNP-NMR in solids. (C) 2011 Elsevier Inc. All rights reserved

Modular set of corrugated wave-guiding components for applications from 500 to 750 GHz

A modular set of compact corrugated wave-guiding components is presented as an alternative to rectangular waveguides in the WR-1.5 band (500 to 750 GHz). The components presented are designed to enable broadband and low loss operation. A high performance connection system between the components allows for modular path building and efficient power coupling to solid-state devices. The manufacturing is based on the "stacked rings" technology. © 2013 IEEE