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Plasmonic Effect on Exciton and Multiexciton Dynamics of Quantum Dots Near Metal Nanostructures

2017 Electronic dissertations
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Release : 2017
Genre : Electronic dissertations
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Book Synopsis Plasmonic Effect on Exciton and Multiexciton Dynamics of Quantum Dots Near Metal Nanostructures by : Swayandipta Dey

Download or read book Plasmonic Effect on Exciton and Multiexciton Dynamics of Quantum Dots Near Metal Nanostructures written by Swayandipta Dey. This book was released on 2017. Available in PDF, EPUB and Kindle. Book excerpt: Recent scientific progress has resulted in the development of sophisticated hybrid nanostructures composed of semiconductor nanocrystals (quantum dots, QDs) and metal nanoparticles (MNPs). These hybrid structures open up new possibilities for developing next generation nanoscale optoelectronic devices that combine the best attributes of each component material.The optical response of MNPs is dominated by surface plasmon resonances which create large local electromagnetic field enhancements. When coupled to surrounding semiconductor components, the enhanced local electric field results in strong absorption/emission, alteration in emission decay rates, enhancement in exciton emission and other interesting non-linear effects (multiphoton generation). Although hybrid nanostructures are poised to be utilized in a variety of applications, serious hurdles for the design of new devices still remain. These difficulties largely result from a poor understanding of how the structural components interact at the nanoscale. These synergetic interactions strongly depend on the exact composition and geometry of the structure, and therefore, a quantitative comparison between theory and experiment is often difficult to achieve. My dissertation work primarily focuses on paving a bridge between the experimental and theoretical studies and the mechanisms involved in exciton and multiexciton emission dynamics of single QDs in presence of plasmonic nanostructures by careful consideration of different parameters which significantly affect the interaction between these nanoparticles at a single particle level.

Exciton-Plasmon Interactions in Metal-Semiconductor Nanostructures

2012-07
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Release : 2012-07
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Book Rating : 198/5 ( reviews)

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Book Synopsis Exciton-Plasmon Interactions in Metal-Semiconductor Nanostructures by : Yikuan Wang

Download or read book Exciton-Plasmon Interactions in Metal-Semiconductor Nanostructures written by Yikuan Wang. This book was released on 2012-07. Available in PDF, EPUB and Kindle. Book excerpt: Over the past decades, the use of surface plasmons (SPs) of noble metal nano-particles to control light emission on the nanometer scale has increased rapidly, due to their field enhancement and other special properties. With this boom in physics, chemistry, biomedical science and engineering has also come a rise in the need for understanding the dynamics of light emission in these systems. Traditional photoluminescence spectrum only gives limited information on quantum dot emission under SP resonances. This book, therefore, uses modern Time-Correlated Single Photon Counting technique and other approaches to study SPs in nanoparticle arrays, and their effects on semiconductor quantum dot emission. The observed SP resonances in metal nano-disc arrays enhances the CdSe/ZnS (core/shell) quantum dot emission in a way that is dependent on dipole emission angle and photon polarization, which is fully explained by quantum electrodynamics. This fundamental finding could be used to control the light emission in plasmonic device applications.

Plasmonic Effects in Metal-semiconductor Nanostructures

2015 Science
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Release : 2015
Genre : Science
Kind : eBook
Book Rating : 313/5 ( reviews)

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Book Synopsis Plasmonic Effects in Metal-semiconductor Nanostructures by : Alexey A. Toropov

Download or read book Plasmonic Effects in Metal-semiconductor Nanostructures written by Alexey A. Toropov. This book was released on 2015. Available in PDF, EPUB and Kindle. Book excerpt: One of the most promising trends in modern nanophotonics is the employment of plasmonic effects in the engineering of advanced device nanostructures. This book implements the binocular vision of such a complex metal-semiconductor system, examining both the constituents and reviewing the characteristics of promising constructive materials.

Orientational and Quantum Plasmonic Effects in the Optics of Metal Nanoparticles

2014
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Release : 2014
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Book Rating : 129/5 ( reviews)

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Book Synopsis Orientational and Quantum Plasmonic Effects in the Optics of Metal Nanoparticles by :

Download or read book Orientational and Quantum Plasmonic Effects in the Optics of Metal Nanoparticles written by . This book was released on 2014. Available in PDF, EPUB and Kindle. Book excerpt: The classical theory of plasmonics envisions spherical nanoparticles obeying classical electrodynamics. Modern colloidal synthesis of noble metal nanoparticles, in tandem with emerging methods of nanoparticle assembly, transcends the assumptions of this theory. First, strongly nonspherical particles give rise to optical spectra with complicated orientation dependence. An interpolation method is introduced to connect electrodynamic simulation results, generally carried out at fixed orientations, with experimental optical spectra, such as those of randomly oriented ensembles. Second, the ability to manipulate and arrange multiple spherical particles in solution with optical binding demands efficient calculation of the optical forces giving rise to their preferred geometries. A coupled-dipole model is developed to allow for rapid optical force calculations that predict many of the phenomena seen in the laboratory. Third, the prospect of attaching semiconductor quantum dots to metal nanoparticles in the electromagnetic near-field raises new questions about how the quantum behavior of localized surface plasmons affects the nonlinear optical response of the coupled system. Investigating such questions yields several new predictions about the optical response of plasmon-exciton systems. Under ultrafast pulsed illumination, a reversal of a Fano resonance is predicted, turning a dip into a spike in the pulsed optical spectrum. When two quantum dots are coupled to the same metal nanoparticle, it is found that their individual couplings to a quantized plasmon can give rise to coherence between the quantum dots, in particular a state enriched in an antisymmetric dark excitation that can be prepared with pulsed laser illumination. These theoretical tools and predictions, in addition to providing basic insight into plasmonic systems, will serve to guide further developments in colloidal synthesis, nanoparticle assembly, and optical applications.

Plasmonic Control of Light Emission

2010
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Release : 2010
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Book Synopsis Plasmonic Control of Light Emission by : Young Chul Jun

Download or read book Plasmonic Control of Light Emission written by Young Chul Jun. This book was released on 2010. Available in PDF, EPUB and Kindle. Book excerpt: Enhanced light-matter interactions in light-confining structures (such as optical cavities) have been extensively investigated for both fundamental studies and practical applications. Plasmonic nanostructures, which can confine and manipulate light down to ~1 nm scale, are becoming increasingly important. Many areas of optical physics and devices can benefit from such extreme light concentration and manipulation. For example, fluorescent molecule or quantum dot (QD) emission can be strongly modified and controlled via surface plasmon polariton (SPP) coupling. In this dissertation, we present our theoretical and experimental studies on QD emission in metal nanogap structures that can provide extreme field concentration, enhancing light-matter interactions significantly. We start with a theoretical analysis of dipole emission in metal-dielectric-metal (MDM) waveguide structures. We look at both infinite (i.e. planar) and finite thickness MDM structures. We find that both structures exhibit strong spontaneous emission enhancements due to the tight confinement of modes between two metallic plates and that light emission is dominated by gap SPP coupling. For planar structures we present analytical solutions for the enhanced dipole decay rate, while for finite thickness MDM structures (i.e. nanoslits) we present results from numerical simulations. Next, we present our experiments on the SPP coupling of CdSe/ZnS QD emission in metal nanoslits. First, we observed clear lifetime and polarization state changes of QD emission with slit width due to gap SPP excitation. Second, with optimized side grooves (i.e. combined slit-groove and hole-groove structures), we collimated QD emission vertically into a very narrow angle, achieving an unprecedented level of directionality control, and visualized it with confocal scanning microscopy. Third, by using two metal plates as electrodes, we dynamically modulated the QD emission intensity and wavelength with external voltage. Finally, we extend our dipole emission calculation to several slot waveguide structures. We consider light emission in metal slots, metal-oxide-Si slots, and Si slot waveguides. We find that large spontaneous emission enhancements can be obtained over a broad range of wavelengths and that light emission is strongly funneled into slot waveguide modes. These represent broadband waveguide QED (quantum electro-dynamics) systems, which have unique merits for on-chip light sources and quantum information processing. These theoretical and experimental studies show that the SPP coupling of light emission is a very promising way to control light emission properties and may find broad application in spectroscopy, sensing, optoelectronics, and integrated optics.

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