Abstract-Impact of Antenna Design on the Electric-Field Direction Sensitivity of Zero-Biased Y–Ba–Cu–O Detectors to Ultra-Short THz Pulses

Alexander Schmid,  Artem Kuzmin  , Johannes L. Steinmann, Juliane Raasch,  Stefan Wuensch,  Konstantin Ilin, Anke-Susanne Müller, Michael Siegel,

https://ieeexplore.ieee.org/document/8645658

Detectors made from sub-micron-sized bridges of the high- Tc superconductor Y–Ba–Cu–O have unique properties useful for the detection of THz radiation, namely evidence of a detector response with an additional sensitivity to the direction of the electric field of short THz pulses when used without a transport current in the so-called “zero-bias” regime. In order to examine the influence of the antenna design on the detector response, we have conducted electromagnetic simulations and performed experiments at a synchrotron light source and with a photomixing setup as sources for short THz pulses. In this paper, we evaluate a narrow-band double-slot antenna as well as a broadband log-spiral antenna design

Abstract-Fast mapping of terahertz bursting thresholds and characteristics at synchrotron light sources

Miriam Brosi, Johannes L. Steinmann, Edmund Blomley, Erik Bründermann, Michele Caselle, Nicole Hiller, Benjamin Kehrer, Yves-Laurent Mathis, Michael J. Nasse, Lorenzo Rota, Manuel Schedler, Patrik Schönfeldt, Marcel Schuh, Markus Schwarz, Marc Weber, and Anke-Susanne Müller

http://journals.aps.org/prab/abstract/10.1103/PhysRevAccelBeams.19.110701

Dedicated optics with extremely short electron bunches enable synchrotron light sources to generate intense coherent THz radiation. The high degree of spatial compression in this so-called low-αc optics entails a complex longitudinal dynamics of the electron bunches, which can be probed studying the fluctuations in the emitted terahertz radiation caused by the microbunching instability (“bursting”). This article presents a “quasi-instantaneous” method for measuring the bursting characteristics by simultaneously collecting and evaluating the information from all bunches in a multibunch fill, reducing the measurement time from hours to seconds. This speed-up allows systematic studies of the bursting characteristics for various accelerator settings within a single fill of the machine, enabling a comprehensive comparison of the measured bursting thresholds with theoretical predictions by the bunched-beam theory. This paper introduces the method and presents first results obtained at the ANKA synchrotron radiation facility.

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