Berlin 2024 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 18: Superconductivity: Poster
TT 18.54: Poster
Monday, March 18, 2024, 15:00–18:00, Poster C
Fabrication of over-coupled transmission line resonators for broadband microwave spectroscopy — •Chiun Fu1,2, Georg Mair1,2, Niklas Bruckmoser1,2, Jianpeng Chen1,2, Rudolf Gross1,2,3, and Nadezhda Kukharchyk1,2,3 — 1Technical University of Munich, School of Natural Sciences, Garching, Germany — 2Walther-Meißner-Institute, Bavarian Academy of Sciences and Humanities, Garching, Germany — 3Munich Center for Quantum Science and Technology (MCQST), Munich, Germany
Spin ensembles are promising for the development of developing quantum memories [1]. However, coupling the spins of rare-earth ions with narrow bandwidth microwave resonators limits their operation to a narrow frequency range. We design over-coupled resonators to reduce their quality factor and thereby expand the bandwidth available for the coupled spin-photon system. Here, we introduce the over-coupled coplanar transmission line (oCPTL) resonator having an interdigital capacitor structure between the linear taper and meandered transmission line. Increasing the coupling capacitance results in an increasing bandwidth of the resonator available for coupling to the rare-earth spin ensembles. The design of the over-coupled transmission line resonators, fabrication details, and the measurement results at cryogenic temperatures will be discussed.
[1] M. Guo, S. Liu, W. Sun et al., Front. Phys. 18, 21303 (2023)
[2] M. Göppl, A. Fragner, M. Baur et al. J. Appl. Phys. 104, 113904 (2008)
Keywords: quantum memory; rare-earth ions; coplanar waveguides; electron spin resonance