E. de Rijk

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 HE(11) mode. This simple concept opens the way for corrugated wave-guides up to several terahertz, maintaining beam characteristics as for terahertz applications.

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.

Study of additive manufactured microwave cavities for pulsed optically pumped atomic clock applications

Additive manufacturing (AM) of passive microwave components is of high interest for the cost-effective and rapid prototyping or manufacture of devices with complex geometries. Here, we present an experimental study on the properties of recently demonstrated microwave resonator cavities manufactured by AM, in view of their applications to high-performance compact atomic clocks. The microwave cavities employ a loop-gap geometry using six electrodes. The critical electrode structures were manufactured monolithically using two different approaches: Stereolithography (SLA) of a polymer followed by metal coating and Selective Laser Melting (SLM) of aluminum. The tested microwave cavities show the desired TE011-like resonant mode at the Rb clock frequency of ≈6.835 GHz, with a microwave magnetic field highly parallel to the quantization axis across the vapor cell. When operated in an atomic clock setup, the measured atomic Rabi oscillations are comparable to those observed for conventionally manufactured cavitie...

Mm-wave antennas and components: Profiting from 3D-printing

The goal of this manuscript is to show the potential of additive manufacturing (AM) to produce cost-effective high-performance passive mm-wave components and antennas. We focus on the particular AM technique developed by SWISSto12 based on the so called Stereolithography (SLA), which consists on the 3D-printing of a skeleton of the component using a non-conductive polymer. Chemical copper plating is then applied in order to make all component surfaces RF-conductive. One of the most relevant advantages associated to this approach stems from its ability to produce low-weight monolithic devices. Two 3D-printed RF-devices operating at mm-waves are here presented: a Ka-band radiating element and a V-band orthomode-transducer. Both devices have been firstly designed using full-wave solvers, then manufactured and finally validated through measurements.