April 11th - Ultralow dissipation nanomechanical resonators for sensing and quantum optomechanics
Friday Physics Colloquia
The Friday Physics Colloquia at the Department of Physics are open to all. An important goal for the colloquia is to be a meeting place between faculty and students to learn about interesting developments in physics.
Undergraduate students are especially encouraged to attend. Speakers are asked to keep the talks at a level targeting a master student in physics.
Speaker: Nils Johan Engelsen, Assistant Professor, Chalmers University of Technology, Sweden
Time: 14:15-15:15
Place: R10 (map)
Title: Ultralow dissipation nanomechanical resonators for sensing and quantum optomechanics
Abstract: 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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