25–28 Nov 2025
Albano Building 3
Europe/Stockholm timezone

Nils Johan Engelsen (Chalmers): Ultralow dissipation nanomechanical resonators for sensing and quantum optomechanics

26 Nov 2025, 11:30
30m
Albano Building 3

Albano Building 3

Hannes Alfvéns väg 12, 10691 Stockholm, Sweden

Speaker

Nils Johan Engelsen (Chalmers)

Description

Nanomechanical oscillators are among the most sensitive force and acceleration sensors and show promise as a quantum technology. However, their performance is fundamentally limited by mechanical dissipation, which admits thermomechanical noise from the environment, limiting force sensitivity, and cuts down the coherence time of mechanical quantum states. Over the last decade, the phenomenon ‘dissipation dilution’ has been exploited to reduce the dissipation of nanomechanical resonators by three orders of magnitude; thereby allowing nanomechanical oscillators to surpass the quality factors of the best macroscopic oscillators. I will explain how dissipation dilution works and how it is greatly enhanced by engineering the resonator geometry. I will then show how we use an ultrahigh-Q membrane in a Fabry-Pérot optical cavity to demonstrate quantum optomechanical effects at room temperature—a longstanding challenge in the field.

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