With the unique advantage of great isolation from the thermal environment, levitated optomechanics has emerged as a powerful platform for various fields of physics
including microscopic thermodynamics, precision measurements, and quantum mechanics. Experiments with optically levitated micro- and nanoparticles have already
obtained remarkable feats of zeptonewton force sensing and ground-state cooling. The
novel system has also been proposed to assess various theories including the objective
collapse models and macroscopic quantum mechanics. <br><div><br></div><div>This thesis reports experimental results on a levitated Cavendish torsion balance,
a GHz nanomechanical rotor, and a torque sensor with unprecedented sensitivity realized with optically levitated nanoparticles in a vacuum environment. The system at
room temperature achieves a sensitivity of (4.2±1.2)×10−27Nm/
√
Hz surpassing the
sensitivity of most advanced nanofabricated torque sensors at cryogenic environments.
Calculations suggest potential detection of Casimir torque and vacuum friction under
realistic conditions. Moreover, the nanoparticles are driven into ultrafast rotations
exceeding 5 GHz, which achieves the fastest humanmade nanomechanical rotor. Such
fast rotations allow studies on the ultimate tensile strength of the nanoparticles as
well. <br></div><div><br></div><div>Subsequently, the electron spin control of nitrogen vacancies (NV) in optically
trapped diamond naoparticles is demonstrated in low vacuum. The configuration is
analogous to trapped atoms and ions which serve as a quantum system with internal states. The effect of the air pressure, surrounding gas, and laser power on the
electron spin resonance (ESR) are studied, and the temperature of the diamond is also measured with the ESR. The levitated nanodiamonds will provide the means to
implement a hybrid spin-optomechanical system.<br></div>
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/12658481 |
| Date | 05 August 2020 |
| Creators | Jonghoon Ahn (9127940) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Relation | https://figshare.com/articles/thesis/Spin_Optomechanics_of_Levitated_Nanoparticles/12658481 |
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