Probing Light-Matter Interactions between Plasmonic Nanoantennas and Single Emitters: Polarization and Localization
Zuo, Tiancheng
2020
Abstract
Single-molecule super-resolution imaging enables optical microscopy to study features of nanometer size. It has been widely used in bioimaging. Plasmonic nanoantennas couple the far field to the near field by converting propagating waves to localized fields. Plasmonic nanoantennas enhance applications from biosensing to light-emitting devices and Raman spectroscopy. Combining single-molecule imaging and plasmonic nanoantennas not only enables plasmon enhanced super-resolution imaging but also provides a unique method to study the light-matter interaction between single molecules and plasmonic nanoantennas. In this thesis, I focus on studying the emission coupling between single emitters and plasmonic particles. Chapter I details the background of single-molecule fluorescence imaging, some fundamental physics behind plasmonic nanoantennas and some nanofabrication techniques used in this thesis. In Chapter II, I discuss my application of single-molecule polarization resolved microscopy to study the emission polarization change of isolated fluorescent emitters with different colors upon coupling to gold nanorods. With the support of simulations, I show that the emission polarization from the coupled system rotates toward the direction of the dominant nanoantenna-localized surface plasmon mode. I also present a reduced-order analytical model that was informed by my experiments to explain the emission polarization modification. The model attributes this emission polarization distribution to both far-field interference and resonant coupling between the molecular dipole and the nanorod plasmon modes. To study emission localization modification (the mislocalization effect), in Chapter III, I use the super-resolution imaging method of dSTORM to image the coupling of single emitters to gold nanodisks. I demonstrate that mislocalization is the result of fluorescence emission coupling, whereas fluorescence enhancement is the result of both absorption and emission coupling. I also discuss how the analytical model is developed further to recover the orientation and localization of a single emitter in the simulation. I show that this model fitting outperforms the standard Gaussian fitting significantly. In addition to the study of organic fluorescent molecules, I use quantum dots (semiconductor nanocrystals, QDs) for super-resolution imaging in Chapter IV. I present the methods that I developed to adapt our organic dye experiments for QDs. I discuss the possibility of using QDs and silver nanoparticles to achieve plasmon enhanced fluorescence without emission coupling. I also characterize by two-channel single-molecule hyperspectral imaging to the spectral shift (bluing) of single QDs upon photooxidation and I discuss how a proximal gold nanoparticle affects the bluing. Lastly, in Chapter V, I present a relevant future direction for doing single-QD imaging with aluminum nanoparticles. It provides a possible approach to achieving plasmon enhanced super-resolution imaging with reduced mislocalization. The work presented in this thesis improves our understanding of the light-matter interactions between plasmonic nanoantennas and single emitters. It also advances the application of plasmon enhanced super-resolution microscopy.Subjects
Single-molecule fluorescence imaging Plasmonic super-resolution imaging optical nanoantennas
Types
Thesis
Metadata
Show full item recordCollections
Remediation of Harmful Language
The University of Michigan Library aims to describe library materials in a way that respects the people and communities who create, use, and are represented in our collections. Report harmful or offensive language in catalog records, finding aids, or elsewhere in our collections anonymously through our metadata feedback form. More information at Remediation of Harmful Language.
Accessibility
If you are unable to use this file in its current format, please select the Contact Us link and we can modify it to make it more accessible to you.