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.

This dissertation describes an approach and a model for the analysis of critical parameters related to the optical and electronic components of spectroscopy systems. The model described herein enables a systematic study of the impact of these parameters on the total performance of the system; therefore, it is a tool for the design and optimization of spectrometers.Although the physics of the optical and electronic components in spectroscopy systems are known and well established, the systemic approach to the understanding of their interactions is recent and it is an area of active research. The results from this study are at several levels: from an engineering perspective, the method developed based on an integrated spectroscopy model enables not only the study of the interactions between the components of the spectrometer, but also the design and optimization of spectrometers for specific applications. From the signal analysis point of view, the understanding of the inter actions between components enables a better identification and filtering of the noise. From the applications point of view, the resulting integrated model enables the translation of data between different spectrometer systems through appropriate compensation algorithms.The approach followed in this dissertation is based on the integration of the models of each one of the components of a spectro-photometer: slit, grating, collimating elements, photo-detectors and analog-to-digital converters. An important contribution of this research has been the simplification of the diffraction grating model. The simplification of the diffraction grating model enables the implementation of a general spectrometer model with two important characteristics: first, it facilitates the analysis of the effect of the parameters of the spectrometer on the spectra readings; second, it allows a computational efficient simulation of the complete model of the spectrometer.The simplified spectrometer model present ed in this dissertation predicts the instrumental effects detected in observed spectra. The results obtained with the model are validated against measured spectra of polystyrene particles suspended in de-ionized water. It is demonstrated that the integrated spectrometer model is capable of representing all the instrumental effects identified.

This work is comprised of the study of two magneto-optical phenomena: the Kerr effect and the Faraday effect. Neutron physics experiments often utilize polarized neutrons, and one method to generate or guide polarized neutrons involves the use of a system of magnetic super-mirrors. Experience shows that the magnetization of the super-mirror may decay with time; therefore, we implemented the surface magneto-optical Kerr effect (SMOKE) to study the temporal behavior of the magnetization of a magnetized remnant super-mirror sample, where a sensitivity of 0.1 mrad was obtained. Unique to our set-up was the method in which the various magnetization directions were probed. The sample was magnetized prior to insertion into the set-up, and a high precision rotational stage was used to manually rotate the sample to effectively generate a reversal of the magnetic field. Multiple samples from a larger super-mirror specimen were tested, in which no change in the magnetization was detected for one month after sample magnetization. Further studies could increase the sensitivity of the experiment, potentially rendering the method as an application for real-time magnetization monitoring. Polarized 3He nuclei are often used as an effective polarized neutron target at various laboratories, including Jefferson Lab, through the use of spin-exchange optical pumping in a glass cell constructed of GE-180. Utilizing the nuclear spin optical rotation to measure the Faraday effect of polarized 3He would develop a new procedure for polarization monitoring, establish a powerful tool to diagnose the wall properties and thicknesses of the cells used, and the determination of the frequency independent magnetic component of the polarizability would ultimately lead to the extraction of the spin polarizability of 3He. Furthermore, this study has the future implications of being the pioneer experiment for terrestrial dark matter studies. A new triple modulation technique was devised, where a sensitivity of 60 nrad was obtained, and the first ever extraction of the Verdet constant of GE-180 was recorded, an important factor in wall thicknesses and diagnostic investigations for Jefferson Lab. However, a measurement of the nuclear spin optical rotation of a polarized 3He target was not realized, as the measured polarization suggests a Faraday rotation just below the 60 nrad threshold. Nevertheless, the devised triple modulation method proves to be a very sensitive probe in Faraday effect studies, and additional examination of the polarized target for the production of a larger polarization, should yield a measurement of the nuclear spin optical rotation of polarized 3He.

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No description available.

Microphotonics has been offering a body of ideas to prospective applicationsin optics. Among those, the concept of photonic integrated circuits (PIC’s) has recently spurred a substantial excitement into the scientific community. Relisation of the PIC’s becomes feasible as the size shrinkage of the optical elements is accomplished. The elements based on photonic crystals (PCs) represent promising candidacy for manufacture of PIC’s. This thesis is devoted to tailoring of optical properties and advanced modelling of two types of photonic crystals: (Bi3Fe5O12/Sm3Ga5O12)m and (TiO2/Er2O3)m potentially applicable in the role optical isolators and optical amplifiers, respectively. Deposition conditions of titanium dioxide were first investigated to maximise refractive index and minimise absorption as well as surface roughness of titania films. It was done employing three routines: deposition at elevated substrate temperatures, regular annealing in thermodynamically equilibrium conditions and rapid thermal annealing (RTA). RTA at 500 oC was shown to provide the best optical performance giving a refractive index of 2.53, an absorption coefficient of 404 cm−1 and a root-mean-square surface roughness of 0.6 nm. Advanced modelling of transmittance and Faraday rotation for the PCs (Bi3Fe5O12/Sm3Ga5O12)5 and (TiO2/Er2O3)6 was done using the 4 × 4 matrix formalism of Višňovský. The simulations for the constituent materials in the forms of single films were performed using the Swanepoel and Višňovský formulae. This enabled generation of the dispersion relations for diagonal and off-diagonal elements of the permittivity tensors relating to the materials. These dispersion relations were utilised to produce dispersion relations for complex refractive indices of the materials. Integration of the complex refractive indices into the 4 × 4 matrix formalism allowed computation of transmittance and Faraday rotation of the PCs. The simulation results were found to be in a good agreement with the experimental ones proving such a simulation approach is an excellent means of engineering PCs.

There is an in-between space during the act of seeing. The in-between space lies on the spectrum of the reality in front of us and what our brain tells us. It is within this suspended moment an individual can experience an unaltered and unaffected vision. While this moment is fleeting, it defines the highest peak of personal experience. It is my belief no two people will ever experience the same vision during this suspended time. And after it passes, the sigh/vision can never be the same. We are constantly bearing witness to the inexpressive, and this fleeting moment is something in which we should all revel.

Les micros ou nanostructures diffractantes sont utilisées depuis de nombreuses années pour sécuriser les documents sensibles, comme les cartes d'identité, les documents de voyage tels que passeports, visas, ou encore les documents fiduciaires. Cependant, le développement des techniques de reprographie et l'implication croissante des organisations criminelles rendent la contrefaçon des documents imprimés de plus en plus accessible. Jusqu'ici, les techniques de fabrication et surtout de réplication des structures diffractantes utilisées pour la protection anti-fraude imposaient une limitation sur l'épaisseur des structures qui typiquement ne pouvaient pas dépasser quelques centaines de nanomètres. Mes travaux de thèse s'inscrivent dans la recherche puis le développement des techniques, très avant-garde, de réalisation et de réplication de structures comportant un relief vertical pouvant atteindre plusieurs microns. La disponibilité de ce type de structures épaisses ouvre de nombreuses possibilités de nouvelles fonctions optiques et donc une nouvelle barrière importante contre la falsification des documents de sécurité. / Diffractive micro/nano structures are used for many years to secure sensitive documents such as identity cards, travel documents (passports, visas...). However, the development of reprographic techniques and the increasing involvement of criminal organizations make counterfeiting of printed documents more accessible. Until now, the manufacturing techniques and especially replication of diffractive structures used for anti-fraud protection imposed a limitation on the thickness of the structures that typically could not exceed a few hundred nanometers. My PhD work is part of the research and the development of very advanced mastering and replication techniques which can, thereafter, realize structures with a vertical relief of up to several microns. The availability of this type of thick structure opens many possibilities for new optical functions and thus a new major barrier against counterfeiting.

The eye is our window to the world. Human vision has therefore been extensively studied over the years. However, in-depth studies are often either limited to our central visual field, or, when extended to the periphery, only correct optical errors related to a narrow spectrum of light. This thesis extends the current knowledge by considering the full visible spectrum over a wide visual field. A broad spectrum means that the wavelength dependence of light propagation inside the eye has to be considered; the optics of the eye will therefore not form a retinal image in the same location for all wavelengths, a phenomenon called chromatic aberration. We present here a new methodology to objectively measure the magnitude of transverse chromatic aberration (TCA) across the visual field of the human eye, and show that the ocular TCA increases linearly with off-axis angle (about 0.21 arcmin per degree for the spectral range from 543 nm to 842 nm). Moreover, we have implemented adaptive psychophysical methods to quantify the impact of TCA on central and peripheral vision. We have found that inducing additional TCA degrades peripheral grating detection acuity more than foveal resolution acuity (more than 0.05 logMAR per arcmin of induced TCA peripherally compared to 0.03 logMAR/arcmin foveally). As stimuli to evaluate peripheral vision, we recommend gratings that are obliquely-oriented relative to the visual field meridian. The results of this thesis have clinical relevance for improving peripheral vision and are equally important for retinal imaging techniques. To limit the negative impacts of TCA on vision, inducing additional TCA should be avoided when the peripheral refractive errors are to be corrected, such as for people suffering from macular degeneration and central visual field loss. In retinal imaging applications, TCA leads to lateral offsets when imaging is performed in more than one wavelength. Consequently, the measurement of TCA together with careful pupil alignment and subsequent compensation can improve the functionality of these instruments. / Ögat är vårt fönster mot världen, och syn har mätts och studerats i stor utsträckning över åren. Trots detta är forskningen om mänsklig syn oftast begränsad till det centrala synfältet, och i studier av det perifera synfältet korrigeras optiska fel endast över ett smalt våglängdsområde. Denna avhandling vidgar forskningen om vår syn till att inkludera hela det synliga spektrumet över ett stort synfält. Ett brett spektrum innebär att vi måste ta hänsyn till våglängdsberoendet i ljusets brytning i ögat; ögats optik kan därför inte avbilda ett objekt till samma bildläge på näthinnan för alla våglängder, ett fenomen som kallas kromatisk aberration. Vi presenterar här en ny metod för att mäta mängden transversell kromatisk aberration (TCA) över ögats synfält och visar att ögats TCA ökar linjärt med vinkeln ut i synfältet (ungefär 0,21 bågminuter per grad från 543 nm till 842 nm). Dessutom har vi implementerat adaptiva psykofysiska mätmetoder för att kvantifiera effekten av TCA på central och perifer syn. Våra resultat visar att extra inducerad TCA påverkar den perifera förmågan att upptäcka sinusformade randmönster mer än den centrala förmågan att upplösa motsvarande ränder (mer än 0,05 logMAR per bågminut inducerad TCA i periferin jämfört med 0,03 logMAR/bågminut centralt). Vid utvärdering av perifer syn rekommenderar vi att använda sinusformade randmönster med en sned riktning jämfört med synfältsmeridianen. Resultaten som presenteras i avhandlingen har klinisk betydelse för att förbättra den perifera synen och är även viktiga för tekniker som avbildar ögats näthinna. För att begränsa den negativa effekt TCA har på synen ska man undvika att inducera extra TCA, t.e.x. när ögats perifera refraktiva fel korrigeras med glasögon för människor med makula degeneration och centralt synfältsbortfall. Vid avbildning av näthinnan ger ögats TCA förskjutningar mellan bilder i olika våglängder. Därför kan mätningar av TCA, tillsammans med välkontrollerad linjering av pupillens position och efterföljande kompensation, förbättra funktionen hos dessa instrument. / <p>QC 20160511</p>

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