Regensburg 2025 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 11: Superconductivity: Poster

TT 11.59: Poster

Monday, March 17, 2025, 15:00–18:00, P4

Dissipative Microwave Optomechanics with a Carbon Nanotube — •Anton Weber, Katrin Burkert, Akong Loh, Niklas Hüttner, and Andreas K. Hüttel — Institut for Experimental and Applied Physics, University of Regensburg, 93053 Regensburg, Germany

High-frequency nanomechanical resonators are valuable for many measurement applications. We investigate a high quality factor mechanical resonator consisting of a suspended carbon nanotube. The nanotube is actuated by applying an external radiofrequency signal. Its motion can modulate its conductance, allowing for electrical detection [1]. In order to transfer this type of experiment from time-averged, dc measurement to fast GHz detection, the nanotube can be integrated into a microwave reflectometry setup at low temperature. A Quartz tuning-fork based carbon nanotube transfer is used to insert the bottom-up grown CNTs into the top-down designed circuit geometry [2]. The specific electronic and mechanical properties of CNTs require adaptation to the microwave circuit; a stub tuner, formed from coplanar waveguides (CPWs), is used for this purpose. They are particularly suitable for high impedance CNTs, as their resonant frequencies and impedance behavior can be precisely controlled by their geometry. The nanotube vibration modulates the signal reflection, effectively resulting in a dissipatively coupled microwave optomechanical system [3].

[1] G. A. Steele et al., Science 325, 5944 (2009).

[2] S. Blien et al., PSSB 255, 180018 (2018).

[3] F. Elste et al., Phys. Rev. Lett. 102, 207209 (2009).

Keywords: Carbon Nanotubes; Optomechanics; Nanomechanics; Microwave cavity