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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
361

1D and 2D Photonic Crystal Nanocavities for Semiconductor Cavity QED

Richards, Benjamin Colby January 2011 (has links)
The topic of this dissertation is photonic crystal nanocavities for semiconductor cavity quantum electrodynamics. For the purposes of this study, these nanocavities may be one dimensional (1D) or two dimensional (2D) in design. The 2D devices are active and contain embedded InAs quantum dots (QDs), whereas the 1D devices are passive and contain no active emitters. The 2D photonic crystal nanocavities are fabricated in a slab of GaAs with a single layer of InAs QDs embedded in the slab. When a cavity mode substantially overlaps the QD ensemble, the dots affect the linewidths of the observed modes, leading to broadening of the linewidth at low excitation powers due to absorption and narrowing of the linewidths at high excitation powers due to gain when the QD ensemble absorption is saturated. We observe lasing from a few QDs in such a nanocavity. A technique is discussed with allows us to tune the resonance wavelength of a nanocavity by condensation of an inert gas onto the sample, which is held at cryogenic temperatures. The structural quality at the interfaces of epitaxially grown semiconductor heterostructures is investigated, and a growth instability is discovered which leads to roughness on the bottom of the GaAs slabs. Adjustment of MBE growth parameters leads to the elimination of this roughness, and the result is higher nanocavity quality factors. A number of methods for optimizing the fabrication of nanocavities is presented, which lead to higher quality factors. It is shown that some fundamental limiting factor, not yet fully understood, is preventing high quality factors at wavelengths shorter than 950 nm. Silicon 1D devices without active emitters are investigated by means of a tapered microfiber loop, and high quality factors are observed. This measurement technique is compared to a cross-polarized resonant scattering method. The quality factors observed in the silicon nanocavities are higher than those observed in GaAs, consistent with our observation that quality factors are in general higher at longer wavelengths.
362

Synthesis and electrochemistry of pyrrole derivatives

Millan Barrios, Enrique Jose January 1996 (has links)
No description available.
363

Molecular structure and liquid crystallinity

Santos, Flavio Bezerra dos January 1997 (has links)
No description available.
364

Hydrogen-bond induced mesomorphism in heteromeric systems and studies towards optically non-linear organometallic materials

Price, Daniel James January 1995 (has links)
No description available.
365

Optical and electro-optical properties of chiral mesophases

Gleeson, H. F. January 1986 (has links)
No description available.
366

Modification and use of a time resolved Raman microprobe for viscoelastic studies of liquid crystals

Booth, Kathryn M. January 1988 (has links)
No description available.
367

Incorporation of coloured impurities in sucrose crystals

Grimsey, I. M. January 1989 (has links)
No description available.
368

Organized structures induced in polymeric and liquid crystalline systems by shear deformation

Pople, John January 1996 (has links)
No description available.
369

The synthesis and characterisation of some novel mesogens

Stephens, Michael Julian January 1993 (has links)
No description available.
370

In-situ fibre formation & management of thermotropic liquid crystalline polymers in thermoplastic matrices

Chuah, Siew Peng January 1995 (has links)
No description available.

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