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Cascaded plasmon resonances for enhanced nonlinear optical response
Title
Cascaded plasmon resonances for enhanced nonlinear optical response.
Creator
Toroghi, Seyfollah, Kik, Pieter, Vanstryland, Eric, Kuebler, Stephen, Hagan, David, Belfield, Kevin, University of Central Florida
Abstract / Description
The continued development of integrated photonic devices requires low-power, small volume all-optical modulators. The weak nonlinear optical response of conventional optical materials requires the use of high intensities and large interaction volumes in order to achieve significant light modulation, hindering the miniaturization of all-optical switches and the development of lightweight transmission optics with nonlinear optical response. These challenges may be addressed using plasmonic...
Show moreThe continued development of integrated photonic devices requires low-power, small volume all-optical modulators. The weak nonlinear optical response of conventional optical materials requires the use of high intensities and large interaction volumes in order to achieve significant light modulation, hindering the miniaturization of all-optical switches and the development of lightweight transmission optics with nonlinear optical response. These challenges may be addressed using plasmonic nanostructures due to their unique ability to confine and enhance electric fields in sub-wavelength volumes. The ultrafast nonlinear response of free electrons in such plasmonic structures and the fast thermal nonlinear optical response of metal nanoparticles, as well as the plasmon enhanced nonlinear Kerr-type response of the host material surrounding the nanostructures could allow ultrafast all-optical modulation with low modulation energy. In this thesis, we investigate the linear and nonlinear optical response of engineered effective media containing coupled metallic nanoparticles. The fundamental interactions in systems containing coupled nanoparticles with size, shape, and composition dissimilarity, are evaluated analytically and numerically, and it is demonstrated that under certain conditions the achieved field enhancement factors can exceed the single-particle result by orders of magnitude in a process called cascaded plasmon resonance. It is demonstrated that these conditions can be met in systems containing coupled nanospheres, and in systems containing non-spherical metal nanoparticles that are compatible with common top-down nanofabrication methods such as electron beam lithography and nano-imprint lithography. We show that metamaterials based on such cascaded plasmon resonance structures can produce enhanced nonlinear optical refraction and absorption compared to that of conventional plasmonic nanostructures. Finally, it is demonstrated that the thermal nonlinear optical response of metal nanoparticles can be enhanced in carefully engineered heterogeneous nanoparticle clusters, potentially enabling strong and fast thermal nonlinear optical response in system that can be produced in bulk through chemical synthesis.
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Date Issued
2014
Identifier
CFE0005556, ucf:50272
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0005556
GOLD NANOPARTICLES: SYNTHESIS, PROPERTY STUDY AND APPLCICATIONS FORBIOMOLECULAR DETECTION AND PHOTOTHERMAL THERAPY
Title
GOLD NANOPARTICLES: SYNTHESIS, PROPERTY STUDY AND APPLCICATIONS FORBIOMOLECULAR DETECTION AND PHOTOTHERMAL THERAPY.
Creator
liu, xiong, Huo, Qun, University of Central Florida
Abstract / Description
This dissertation presents a systematic study on gold nanoparticles: from their chemical synthesis, modification of surface functionalities, optical properties studies with emphasis on the absorption and scattering properties, to applications of gold nanoparticles in biomolecular detection, imaging and photothermal therapy. In chapter 2, we studied the kinetics of gold nanoparticle growth under Brust-Shiffrin reaction conditions. In chapter 3, we further examined the reaction mechanism and...
Show moreThis dissertation presents a systematic study on gold nanoparticles: from their chemical synthesis, modification of surface functionalities, optical properties studies with emphasis on the absorption and scattering properties, to applications of gold nanoparticles in biomolecular detection, imaging and photothermal therapy. In chapter 2, we studied the kinetics of gold nanoparticle growth under Brust-Shiffrin reaction conditions. In chapter 3, we further examined the reaction mechanism and growth kinetics of gold nanoparticles using oleylamine as both a reducing reagent and particle growth passivation ligand. From these two projects, important understanding was revealed on gold nanoparticle formation and growth mechanism. Chapter 4 describes the synthesis of a monofunctional gold nanoparticle through a solid phase place exchange reaction. From Chapter 5, we moved to the optical property study of gold nanoparticles, particularly the absorption and scattering phenomenon. In this work a systematic analysis on the extinction coefficient of gold nanoparticles was performed, providing meaningful references for applications based on optical absorption properties of gold nanoparticles. In Chapter 6 and Chapter 7, we developed a one-step homogeneous immunoassay for protein detection and analysis based on the strong light scattering of gold nanoparticles and dynamic light scattering detection technique. In Chapter 8, we further improved the stability of gold nanoparticle bioconjugates using a poly(ethylene glycol)-coated gold nanoparticles and further tested this nanoparticle in the one-step homogeneous immunoassay. Finally in Chapter 9, we demonstrated the application of gold nanoparticles for in vitro bioimaging and photothermal therapy of a lung cancer cell. In summary, this dissertation presents a comprehensive study on the synthesis, surface modification, property study of gold nanoparticles and their applications in biomolecular imaging and analysis.
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Date Issued
2009
Identifier
CFE0002874, ucf:48020
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0002874
SURFACE ENGINEERING OF GOLD NANOPARTICLES AND THEIR APPLICATIONS
Title
SURFACE ENGINEERING OF GOLD NANOPARTICLES AND THEIR APPLICATIONS.
Creator
Dai, Qiu, Huo, Qun, University of Central Florida
Abstract / Description
Gold nanoparticles (AuNPs) with their unique sizes, shapes, and properties have generated much enthusiasm over the last two decades, and have been explored for many potential applications. The successful application of AuNPs depends critically on the ability to modify and functionalize their surface to provide stability, compatibility, and special chemical functionality. This dissertation is aimed at exploring the chemical synthesis and surface modification of AuNPs with the effort to (1)...
Show moreGold nanoparticles (AuNPs) with their unique sizes, shapes, and properties have generated much enthusiasm over the last two decades, and have been explored for many potential applications. The successful application of AuNPs depends critically on the ability to modify and functionalize their surface to provide stability, compatibility, and special chemical functionality. This dissertation is aimed at exploring the chemical synthesis and surface modification of AuNPs with the effort to (1) control the number of functional groups on the particle surface, and to (2) increase the colloidal stability at the physiological conditions. To control the functionality on the particle surface, a solid phase place exchange reaction strategy was developed to synthesize the 2 nm AuNPs with a single carboxylic acid group attached on the particle surface. Such monofunctional AuNPs can be treated and used as molecular nanobuilding blocks to form more complex nanomaterials with controllable structures. A "necklace"-like AuNP/polymer assembly was obtained by conjugating covalently the monofunctional AuNPs with polylysine template, and exhibited an enhanced optical limiting property due to strong electromagnetic interaction between the nanoparticles in close proximity. To improve the colloidal stability in the psychological condition, biocompatible polymers, polyacrylic acid (PAA), and polyethylene glycol (PEG) were used to surface modify the 30 nm citrate-stabilized AuNPs. These polymer-modified AuNPs are able to disperse individually in the high ionic strength solution, and offer as the promising optical probes for bioassay applications. The Prostate specific antigen (PSA) and target DNA can be detected in the low pM range by taking advantages of the large scattering cross section of AuNPs and the high sensitivity of dynamic light scattering (DLS) measurement. In addition to the large scattering cross section, AuNPs can absorb strongly the photon energy at the surface plasmon resonance wavelength and then transform efficiently to the heat energy. The efficient photon-thermal energy conversion property of AuNPs has been used to thermal ablate the Aβ peptide aggregates under laser irradiation toward Alzheimer's disease therapy.
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Date Issued
2008
Identifier
CFE0002395, ucf:47767
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0002395
Photothermal Lensing in Mid-Infrared Materials
Title
Photothermal Lensing in Mid-Infrared Materials.
Creator
Cook, Justin, Richardson, Martin, Shah, Lawrence, Gaume, Romain, University of Central Florida
Abstract / Description
A thorough understanding of laser-materials interactions is crucial when designing and building optical systems. An ideal test method would probe both the thermal and optical properties simultaneously for materials under large optical loads where detrimental thermal effects emerge. An interesting class of materials are those used for infrared wavelengths due to their wide spectral transmission windows and large optical nonlinearities. Since coherent sources spanning the mid-wave and long-wave...
Show moreA thorough understanding of laser-materials interactions is crucial when designing and building optical systems. An ideal test method would probe both the thermal and optical properties simultaneously for materials under large optical loads where detrimental thermal effects emerge. An interesting class of materials are those used for infrared wavelengths due to their wide spectral transmission windows and large optical nonlinearities. Since coherent sources spanning the mid-wave and long-wave infrared wavelength regions have only become widely available in the past decade, data regarding their thermal and optical responses is lacking in literature.Photothermal Lensing (PTL) technique is an attractive method for characterizing the optical and thermal properties of mid-infrared materials as it is nondestructive and can be implemented using both continuous wave and pulsed irradiation. Analogous to the well-known Z-scan, the PTL technique involves creating a thermal lens within a material and subsequently measuring this distortion with a probe beam. By translating the sample through the focus of the pump laser, information can be obtained regarding the nonlinear absorption, thermal diffusivity and thermo-optic coefficient. This thesis evaluates the effectiveness and scope of the PTL method using numerical simulations of low loss infrared materials. Specifically, the response of silicon, germanium, and As2Se3 glass is explored. The 2 ?m pump and 4.55 ?m probe beam geometries are optimized in order to minimize experimental error. Methodologies for estimating the thermal diffusivity, nonlinear absorption coefficient and thermo-optic coefficient directly from the experimentally measured PTL signal are presented. Finally, the ability to measure the nonlinear absorption coefficient without the need for high-energy or ultrashort optical pulses is demonstrated.
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Date Issued
2017
Identifier
CFE0006730, ucf:51885
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0006730