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Optomechanics with Superfluid Helium-4


De Lorenzo, Laura Anne (2016) Optomechanics with Superfluid Helium-4. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/Z9RJ4GD7.


We demonstrate the utility of superfluid helium-4 as an extremely low loss optomechanical element. We form an optomechanical system with a cylindrical niobium superconducting TE011 resonator whose 40 cm3 inner cylindrical cavity is filled with 4He. [1] Coupling is realized via the variations in permittivity resulting from the density profile of the acoustic modes. Acoustic losses in helium-4 below 500 mK are governed by the intrinsic nonlinearity of sound, leading to an attenuation which drops as T 4, indicating the possibility of quality factors (Q) over 1010 at 10 mK. In our lowest loss mode, we demonstrate this T 4 law down to 50 mK, realizing an acoustic Q of 1.35·108 at 8.1 kHz. When coupled with a low phase noise microwave source, we expect this system to be utilized as a probe of macroscopic quantized motion, for precision measurements to search for fundamental physical length scales, and as a continuous gravitational wave detector. Our estimates suggest that a resonant superfluid acoustic system could exceed the sensitivity of current broad-band detectors for narrow-band sources such as pulsars [2].

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:superfluid helium, optomechanics, sensitive force detection, gravitational wave detection, minimum length scale
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Applied Physics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Schwab, Keith C.
Group:Institute for Quantum Information and Matter
Thesis Committee:
  • Schwab, Keith C. (chair)
  • Chen, Yanbei
  • Adhikari, Rana
  • Faraon, Andrei
Defense Date:20 May 2016
Record Number:CaltechTHESIS:05272016-075803376
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:9781
Deposited By: Laura DeLorenzo
Deposited On:01 Jun 2016 17:11
Last Modified:02 Jun 2020 21:49

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