No description available.

The thesis explores preparation and properties of bismuthiron garnet (BIG) films and the incorporation of BIG films intoone-dimensional magneto-optical photonic crystals (MOPCs). Films were prepared by pulsed laser deposition. Weinvestigated or measured crystallinity, morphology,film-substrate interface, cracks, roughness, composition,magnetic coercivity, refractive index and extinctioncoefficient, and magneto-optical Faraday rotation (FR) andellipticity. The investigations were partly performed onselected samples, and partly on two series of films ondifferent substrates and of different thicknesses. BIG filmswere successfully tested for the application of magneto-opticalvisualization. The effect of annealing in oxygen atmosphere wasalso investigated - very careful annealing can increase FR byup to 20%. A smaller number of the above mentionedinvestigations were carried out on yttrium iron garnet (YIG)films as well. Periodical BIG-YIG multilayers with up to 25 single layerswere designed and prepared with the purpose to enhance FR at aselected wavelength. A central BIG layer was introduced asdefect layer into the MOPC structure and generated resonancesin optical transmittance and FR at a chosen design wavelength.In a 17- layer structure, at the wavelength of 748 nm, FR wasincreased from -2.6 deg/µm to -6.3 deg/µmat a smallreduction in transmittance from 69% to 58% as compared to asingle-layer BIG film of equivalent thickness. In contrast tothick BIG films, the MOPCs did not crack. We were first toreport preparation of all-garnet MOPCs and second toexperimentally demonstrate the MOPC principle inmagneto-optical garnets.

Abstract In this paper, the optical properties of magnetic fluid thin films are studied. We present the experimental observation of optical linear birefringence and dichroism in magnetic fluid thin film induced by crossed magnetic field perpendicular to the direction of light propagation. According to our results, we ascertain that both the magnetic birefringence and dichroism are existed. Besides, we also find that the relations between magnetic field and magneto-optical effects changed with the applied magnetic field intensity.

<p>The thesis explores preparation and properties of bismuthiron garnet (BIG) films and the incorporation of BIG films intoone-dimensional magneto-optical photonic crystals (MOPCs).</p><p>Films were prepared by pulsed laser deposition. Weinvestigated or measured crystallinity, morphology,film-substrate interface, cracks, roughness, composition,magnetic coercivity, refractive index and extinctioncoefficient, and magneto-optical Faraday rotation (FR) andellipticity. The investigations were partly performed onselected samples, and partly on two series of films ondifferent substrates and of different thicknesses. BIG filmswere successfully tested for the application of magneto-opticalvisualization. The effect of annealing in oxygen atmosphere wasalso investigated - very careful annealing can increase FR byup to 20%. A smaller number of the above mentionedinvestigations were carried out on yttrium iron garnet (YIG)films as well.</p><p>Periodical BIG-YIG multilayers with up to 25 single layerswere designed and prepared with the purpose to enhance FR at aselected wavelength. A central BIG layer was introduced asdefect layer into the MOPC structure and generated resonancesin optical transmittance and FR at a chosen design wavelength.In a 17- layer structure, at the wavelength of 748 nm, FR wasincreased from -2.6 deg/µm to -6.3 deg/µmat a smallreduction in transmittance from 69% to 58% as compared to asingle-layer BIG film of equivalent thickness. In contrast tothick BIG films, the MOPCs did not crack. We were first toreport preparation of all-garnet MOPCs and second toexperimentally demonstrate the MOPC principle inmagneto-optical garnets.</p>

No description available.

Polarization specific measurements are advancing the capabilities of scientific instruments looking for ever smaller effects and material parameters. For example, the magneto-optical nonlinear Faraday effect can be used to characterize various electric and magnetic polarizability parameters of an individual molecule. Another major application is detection of desired particles in a highly scattering environment, the physical effect of which has been extensively researched, and is being overcome by using time-gated and polarization techniques. The polarimeter sensitivity is limited by the extinction-ratio obtained from polarizers. Of available polarizer materials, naturally occurring Calcite crystals provide the best extinction ratios because of their good optical homogeneity and high birefringence. However, there is a need for polarization determination with higher sensitivities, and thus a necessity to find better polarizing materials and methods. I developed a next-generation polarimeter in an attempt to sensitively detect the second-order Faraday effect, along with a substance s chirality and Verdet constant. Also, I developed a device uniquely able to sensitively detect chiral signatures in the presence of massive depolarizing scattering. In addition, I begun developing a novel type of polarimeter based on the highly-polarization-sensitive nonlinear-optical process of harmonic generation, whose required crystals can be grown with extremely high quality.

The advancement of photonics technologies depends on synthesis of novel materials and processes for device fabrication. The characterization techniques of the optical, electrical and magnetic properties of the synthesized materials and devices, by non-contact, non-invasive and nondestructive methods plays a significant role in development of new photonics technologies. The research reported in this thesis focuses on two such aspects of photonic materials characterization: Magneto-Optic characterization and Spectroscopic Ellipsometry. The theoretical and experimental basis of these two techniques, and experimental data analysis are presented in two parts. In Part 1, the changes in magneto-optic parameters of FePT PS-P2VP block copolymer nanocomposites with increasing concentrations of FePt nanoparticles in the block copolymer are analyzed. We present the results of change in MO anisotropy factor with the wt% of FePt and try to analyze these changes with further experimentation. Part 2 presents the results of spectroscopic ellipsometry of group III-IV multilayered thin film materials to give their precise thicknesses and optical constants. Both these techniques are unique ways to understand novel material characteristics for future use in device development.

Este trabalho é dedicado à investigação de diferentes aspectos da física de monocamadas de grafeno suspenso e epitaxial. A descrição do grafeno é baseada no modelo quase-relativístico de Dirac. Isso permite a aplicação dos métodos da Teoria Quântica de Campos (TQC) na investigação dos efeitos de interação entre o grafeno e o campo eletromagnético (EM). Usando o formalismo de integral de trajetória, nós formulamos uma teoria efetiva do campo EM na presença de monocamadas de grafeno. Esta teoria é governada pelo operador de polarização das quase-partículas de Dirac. Dois fenômenos importantes são investigados: as propriedades óticas do grafeno (o efeito Faraday em particular) e a interação de Casimir entre uma camada de grafeno e um metal paralelo. Em primeiro lugar, estudamos a propagação de ondas eletromagnéticas na presença de camadas de grafeno. A dinâmica de ondas é governada pelas equações modificadas de Maxwell obtidas a partir da teoria efetiva para o campo EM. Nós calculamos os coeficientes de reflexão e transmissão de luz polarizada linearmente e investigamos detalhadamente o efeito quântico de Faraday no campo magnético externo. Em particular, mostramos que as previsões do modelo de Dirac estão em boa concordância com os recentes resultados experimentais sobre a transmissão de luz e rotação de Faraday gigante em regime de ressonância cíclotron. Novos regimes também são previstos. Em segundo lugar, investigamos a interação de Casimir entre filmes suspensos de grafeno com um condutor ideal. O efeito é investigado tanto no caso ideal (temperatura nula, amostras ideais) quanto para configurações mais realistas (temperatura não nula e a presença de potencial químico). No caso de temperatura nula, a força de Casimir entre grafeno e condutor ideal é aproximadamente 2.6% da força entre dois condutores ideais. Ao mesmo tempo, no limite de temperatura elevada, o efeito mostra-se ser muito forte cerca de 50% de efeito entre metais ideais. / This research is devoted to investigation of several aspects of the physics of suspended and epitaxial graphene monolayers. The description of graphene is based on the quasi--relativistic Dirac model which permits application of the methods of the Quantum Field Theory to investigation of the interaction of graphene with electromagnetic field. Basing on the path integral formalism we formulate the effective theory for EM field in presence of graphene monolayers which is governed by the polarization operator of the Dirac quasi-particles in graphene. The two main phenomena in the interaction of graphene with electromagnetic field are studied: the optical properties of graphene (the Faraday rotation in particular), and Casimir interaction between graphene samples and parallel metal. First, we study the propagation of electromagnetic waves in presence of suspended and epitaxial graphene layers. Their dynamics is governed by the modified Maxwell equations obtained from the effective theory for EM field. We calculate the reflection and transmission coefficient for linearly polarized light and investigate in detail the quantum Faraday effect in external magnetic field. In particular it is showed that the prediction of the Dirac model are in good agreement with recent experimental results on transmission and giant Faraday rotation in cyclotron resonance. New regimes are also predicted Secondly, we investigate Casimir interaction between suspended graphene films with ideal conductor. The effect is investigated both in the idealistic case (zero temperature, ideal samples) and for realistic configurations (non zero temperature and/or presence of impurities and chemical potential). For zero temperature the Casimir force between graphene and a conductor is about 2.7% of that between two ideal conductors. At the same time in the high temperature limit the effect is showed to be greatly enhanced being about 50% of that between ideal metals.

Gyromagnetic Faraday rotation offers a new method to probe limits on properties of simple spin systems such as the possible magnetic moment of asymmetric dark matter or as a polarization monitor for polarized targets. Theoretical calculations predict the expected rotations of linearly polarized light due to the magnetization of spin-1/2 particles are close to or beyond the limit of what can currently be measured experimentally (10−9 rad). So far, this effect has not been verified. Nuclear spin polarized 3He provides an ideal test system due to its simple structure and ability to achieve high nuclear spin polarization via spin-exchange optical pumping (SEOP). To maximize the expected signal from 3He, a SEOP system is built with a modern narrowband pumping laser and a 3He target designed to use with a multipass cavity. Additionally, a sensitive triple modulation apparatus for polarimetry is utilized and further developed to detect Faraday rotations on the order of nanoradians. This works presents the results of the measurement of the magnetic Faraday effect.

In this thesis, the study of optical properties of magnetic fluid thin films is the main purpose. We measured the intensity of linear polarized laser beam, which passed through our sample, magnetic fluid thin film with external magnetism, to analyze the relationships between magnetic field intensity and magneto-birefringence and magneto-dichroism. According to our experimental results, we ascertain that both the magneto-birefringence and magneto-dichroism are existed. Besides, we found that the difference of index at magnetic fluid thin film changed with magnetic field intensity also. The phenomenon let us believe that magnetic fluid thin film is anisotropy. Moreover, we also applied the statement, which agreed by most physicists to explain what we found from our real measurements.