dc.contributor.advisor Loncar, Marko dc.contributor.author Hui, Pui Chuen dc.date.accessioned 2014-10-21T18:51:40Z dash.embargo.terms 2015-01-01 en_US dash.embargo.terms 2015-01-01 dc.date.issued 2014-10-21 dc.date.submitted 2014 dc.identifier.citation Hui, Pui Chuen. 2014. Optomechanics and nonlinear mechanics of suspended photonic crystal membranes. Doctoral dissertation, Harvard University. en_US dc.identifier.other http://dissertations.umi.com/gsas.harvard.inactive:11841 en dc.identifier.uri http://nrs.harvard.edu/urn-3:HUL.InstRepos:13068536 dc.description.abstract The recent demonstration of strong interactions between optical force and mechanical motion of an optomechanical structure has led to the triumphant result of mechanical ground-state cooling, where the quantum nature of a macroscopic object is revealed. Another intriguing demonstration of quantum physics on a macroscopic level is the measurement of the Casimir force which is a manifestation of the zero- point energy. An interesting aspect of the Casimir effect is that the anharmonicity of the Casimir potential becomes significant when the separation of microscale objects is in the sub-100nm regime. This regime is readily accessible by many of the realized gradient-force-based optomechanical structures. Hence, a new avenue of probing the Casimir effect on-chip all-optically has become available. We propose an integrated optomechanical platform, consisting of a suspended photonic crystal membrane evanescently coupled with a silicon-on-insulator substrate, for (i) measuring the Casimir force gradient and (ii) counteracting the attractive force by exerting a resonantly enhanced repulsive optical gradient force. This thesis first presents the full characterization of the optomechanical properties of the system in vacuo. The interplay of the optical gradient force (optomechanical coupling strength $g_{om}/2\pi=- 66GHz/nm$) and the photothermal force manifested in the optical spring effect and dynamic backaction is elucidated. Static displacement by the repulsive force of 1nm/mW is also demonstrated. en_US In the second part of the thesis, the nonlinear mechanical signatures upon a strong coherent drive are reported. By resonantly driving the photonic crystal membrane with a piezo-actuator and an optical gradient force, we observed mechanical frequency mixing, mechanical bistability and non-trivial interactions of the Brownian peak with the driving signal. Finally we present our recent progress in establishing electro- static control of individual photonic crystal membranes to reduce and calibrate the electrostatic artifact which plagues Casimir measurements. The results discussed in this thesis point towards an auspicious future of a complete realization of a Casimir optomechanical structure and novel applications with nonlinearity afforded by the Casimir force and the optical gradient force. dc.description.sponsorship Engineering and Applied Sciences en_US dc.language.iso en_US en_US dash.license LAA dc.subject Optics en_US dc.subject Physics en_US dc.subject Nano-mechanics en_US dc.subject Nonlinear mechanics en_US dc.subject Optical force en_US dc.subject Optomechanics en_US dc.subject Photonic crystal membrane en_US dc.title Optomechanics and nonlinear mechanics of suspended photonic crystal membranes en_US dc.type Thesis or Dissertation en_US dash.depositing.author Hui, Pui Chuen dc.date.available 2015-01-01T08:31:06Z thesis.degree.date 2014 en_US thesis.degree.discipline Engineering and Applied Sciences en_US thesis.degree.grantor Harvard University en_US thesis.degree.level doctoral en_US thesis.degree.name Ph.D. en_US dc.contributor.committeeMember Loncar, Marko en_US dc.contributor.committeeMember Capasso, Federico en_US dc.contributor.committeeMember Hu, Evelyn en_US dash.contributor.affiliated Hui, Pui Chuen
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