Thesis (M. S.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2007. / Committee Chair: A. Rahman Zaghloul ; Committee Members: W. Russell Callen and Doug Yoder. Part of the SMARTech Electronic Thesis and Dissertation Collection.

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Temperature dependent optical properties of lipid tissue verify critical information of tissue dynamics which can be applied to tissue treatment and diagnosis of various pathological features. Current methods of treating lipid rich tissues via heating are associated with post operation complications. Recent studies shows potential of lipid rich tissue removal by cooling. For monitoring cooling procedure and physical and chemical changes in lipid tissue, temperature dependent optical properties in subzero cooling need to be verified. This study designed heat transfer system estimating heat flux by cooling and programmed codes for image and data processing to obtain refractive indices of rodent subcutaneous lipid tissue. Phase transition of lipid tissue was observed and finally verified temperature dependent refractive index coefficient of lipid tissue from 24°C to -10°C. / text

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Rapid development in nanofabrication has led to the design of new materials with very unusual properties. The exhibition of negative and zero indices of refraction are among the most striking properties of these materials, which have become the focus of intensive research worldwide. The potential for applications that is possible due to the new light manipulation capabilities of these materials has been the driving force behind this research. Most of the research in this field has primarily been experimental while the theoretical studies have mainly been limited to computer modeling, which in itself is a challenging problem. This research requires considerable computational resources and the development of new computer algorithms.The origin of the unusual properties in these materials comes from the combination of dielectric host materials with metallic nanosructures. These materials are often referred to as nanocomposite metamaterials. The plasmonic resonance in properly engineered metallic nanostructures gives rise to the resonant interaction of the incident electromagnetic field with metamaterials in such a way as to stimulate a magnetic permeability and an electric permittivity with negative real parts. The resonant nature of this phenomenon leads to considerable losses in metamaterials, which has made the study of loss compensation one of the key subjects in this field.The two techniques of loss compensation in metamaterials are considered in this dissertation. One of these techniques consists of doping the host material with active atoms. In the second technique, loss compensation is achieved by embedding these active atomic inclusions directly into the nanostructures. This dissertation presents the derivation of the systems of governing equations and studies the coherent pulse amplification for both cases.

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The use of rayon in 1920s and 1930s garments confronts conservators with new challenges: definitive fibre identification involves more than basic microscopy and treatment can be difficult with little available research on early rayon and its conservation. Rayon is expected to degrade similarly to other cellulosic fibres; however, since it is a regenerated fibre, rayon is at risk of doing so at a faster rate. The purpose of this research was to develop and test a protocol for the identification of viscose and cuprammonium rayon and to determine whether early rayon dresses have condition issues at this time. Polarizing microscopy, hot-stage microscopy, acetone solubility and relative fibre refractive index were explored as fibre identification techniques, resulting in the development of a rayon identification scheme. 1920s and 1930s rayon dresses were surveyed for condition and it was determined that dresses in this sample have limited condition issues at this time.

Academisch proefschrift--Amsterdam. / "Summary": p. 141-142. "Stellingen": [2] p. inserted. "Literatuur": p. 143-145.

This thesis presents a method to fabricate a robust optical directional coupler sensor using a solid core fiber (SCF) and a hollow core fiber (HCF). Through evanescent wave coupling mechanism, the optical power is exchanged between SCF and HCF. The hollow core of the HCF can be filled with liquid samples to alter the coupling ratio which imparts change in amount of light propagating through the SCF. Thus, it gives the coupler with ability of sensing refractive index of the sample with good sensitivity of 4.03 ± 0.50 volts per refractive index units (V/RIU) for refractive indices ranging from 1.331 ± 0.003 to 1.403 ± 0.003 with a resolution of 3.5 × 10−3 refractive index units (RIU). The SCF-HCF coupler was also used to sense the temperature based on the concept of temperature dependence on refractive index of the sample inside the hollow core of HCF. Further, the packaging methods are described that protect coupler from ambient environments and improves the life span of sensor. / Graduate