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dc.contributor.advisorRabitz, Herschel Aen_US
dc.contributor.authorXie, Danen_US
dc.contributor.otherChemistry Departmenten_US
dc.date.accessioned2015-12-07T19:58:54Z-
dc.date.available2015-12-07T19:58:54Z-
dc.date.issued2015en_US
dc.identifier.urihttp://arks.princeton.edu/ark:/88435/dsp015999n578f-
dc.description.abstractOptical studies of nano-objects that have dimensions 10 -- 1000 nm have become a flourishing field of research. This special dimension category, connecting the smaller (molecular) world and the larger (cellular) world, have enabled these nano-objects to be widely utilized as novel optical tools in many fields. In addition to the extensive applications of nano objects, increasing efforts are also being put to better understand their interactions with light at a fundamental level. The work presented in this dissertation is part of such efforts, in which I selected three types of nano-objects and studied their optical properties both in theory and experiment. Second-harmonic and sum-frequency generations are among the most well-known nonlinear optical processes. Dielectric nanocrystals that are SHG- and SFG- active are favored tools in bioimaging. For a nanocrystal, its SHG/SFG intensity depends on the geometry of the light-particle system, i.e., the relationship between the nanocrystal orientation and the laser polarization. Using BaTiO3 nanocrystals as an example, I carried out an in-depth, theoretical investigation of such dependence. Particularly, I studied the possibility of selectively maximizing the contrast between light signals from two or more nanocrystals by manipulating laser polarization. I will present a dicussion on how the capacity of this selective illumination depends on the relative orientation between the two nanocrystals and the polarization of the excitation field. The optical responses of non-spherical plasmonic particles, being dynamic and complex, are only partially understood. Gold nanorods (AuNRs) are one of the most popular members in this nanoparticle family. They can produce two-photon luminescence (TPL) and amplify molecular events occuring at their surface. Both phenomena are known to be associated with surface plasmon resonances (SPR) of AuNRs, but details of the mechanisms are yet to be understood and quantified. I constructed a two-photon laser-scanning microscopy system to study these phenomena at the single-particle level. In the experiment, I measured the polarization-dependent TPL emissions from single nanorods that are triggered by time-resolved two-photon excitations. The observation indicates that, different from what was generally believed, the TPL in AuNRs is resulted from two sequentially one-photon absorption process that are both coupled to the longitudinal SPR mode. The studies on the two-photon fluorescence in dyes conjugated with AuNRs confirmed the coherent nature of the two-photon absorption process and provided an estimate of the fluorescence enhancement due to the presence of AuNRs. Molecules with cross-conjugated structures have a special role in molecular electronics. Their inherent quantum interference property can be utilized to create molecular switches with excellent on/off ratio. When a molecular junction is exposed to light, photons may open extra pathways for electron tunneling, and thus modify the conduction properties of the junction. Such modification depends on the electronic structure of the molecule, as well as on the frequency, amplitude, and polarization of the driving field. In collaboration with my colleague, I simulated electron tunneling properties of junctions with cross-conjugated molecules and discussed their dependence on light properties. It is noteworthy that symmetry plays a major role in zero-bias tunneling: the molecule-field systems with general parity show distinct tunneling behaviors from their counterparts without general parity.en_US
dc.language.isoenen_US
dc.publisherPrinceton, NJ : Princeton Universityen_US
dc.relation.isformatofThe Mudd Manuscript Library retains one bound copy of each dissertation. Search for these copies in the library's main catalog: http://catalog.princeton.edu/en_US
dc.subjectgold nanorodsen_US
dc.subjectmolecular junctionen_US
dc.subjectnano-objectsen_US
dc.subjectsurface plasmon resonanceen_US
dc.subjecttwo-photon luminescenceen_US
dc.subjecttwo-photon microscopyen_US
dc.subject.classificationChemistryen_US
dc.subject.classificationOpticsen_US
dc.subject.classificationPhysical chemistryen_US
dc.titleStudies of Interactions Between Nano-Objects and Polarized Lighten_US
dc.typeAcademic dissertations (Ph.D.)en_US
pu.projectgrantnumber690-2143en_US
Appears in Collections:Chemistry

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