The widespread adoption of photonic circuits requires the economics of volume manufacturing offered by integration technology. A Complementary Metal-Oxide Semiconductor compatible silicon material platform is particularly attractive because it leverages the huge investment that has been made in silicon electronics and its high index contrast enables tight confinement of light which decreases component footprint and energy consumption. Nevertheless, there remain challenges to the development of photonic integrated circuits. Although the density of integration is advancing steady and the integration of the principal components – waveguides, optical sources and amplifiers, modulators, and photodetectors – have all been demonstrated, the integration density is low and the device library far from complete. The integration density is low primarily because of the difficulty of confining light in structures small compared to the wavelength which measured in micrometers. The device library is incomplete because of the immaturity of hybridisation on silicon of other materials required by active devices such as III-V semiconductor alloys and ferroelectric oxides and the difficulty of controlling the coupling of light between disparate material platforms. Metamaterials are nanocomposite materials which have optical properties not readily found in Nature that are defined as much by their geometry as their constituent materials. This offers the prospect of the engineering of materials to achieve integrated components with enhanced functionality. Metamaterials are a class of photonic crystals includes subwavelength grating waveguides, which have already provided breakthroughs in component performance yet require a simpler fabrication process compatible with current minimum feature size limitations. The research reported in this PhD thesis advances our understanding of the structure-property relations of key planar light circuit components and the metamaterial engineering of these properties. The analysis and simulation of components featuring structures that are only just subwavelength is complicated and consumes large computer resources especially when a three dimensional analysis of components structured over a scale larger than the wavelength is desired. This obstructs the iterative design-simulate cycle. An abstraction is required that summarises the properties of the metamaterial pertinent to the larger scale while neglecting the microscopic detail. That abstraction is known as homogenisation. It is possible to extend homogenisation from the long-wavelength limit up to the Bragg resonance (band edge). It is found that a metamaterial waveguide is accurately modeled as a continuous medium waveguide provided proper account is taken of the emergent properties of the homogenised metamaterial. A homogenised subwavelength grating waveguide structure behaves as a strongly anisotropic and spatially dispersive material with a c-axis normal to the layers of a one dimensional multi-layer structure (Kronig-Penney) or along the axis of uniformity for a two dimensional photonic crystal in three dimensional structure. Issues with boundary effects in the near Bragg resonance subwavelength are avoided either by ensuring the averaging is over an extensive path parallel to boundary or the sharp boundary is removed by graded structures. A procedure is described that enables the local homogenised index of a graded structure to be determined. These finding are confirmed by simulations and experiments on test circuits composed of Mach-Zehnder interferometers and individual components composed of regular nanostructured waveguide segments with different lengths and widths; and graded adiabatic waveguide tapers. The test chip included Lüneburg micro-lenses, which have application to Fourier optics on a chip. The measured loss of each lens is 0.72 dB. Photonic integrated circuits featuring a network of waveguides, modulators and couplers are important to applications in RF photonics, optical communications and quantum optics. Modal phase error is one of the significant limitations to the scaling of multimode interference coupler port dimension. Multimode interference couplers rely on the Talbot effect and offer the best in-class performance. Anisotropy helps reduce the Talbot length but temporal and spatial dispersion is necessary to control the modal phase error and wavelength dependence of the Talbot length. The Talbot effect in a Kronig-Penny metamaterial is analysed. It is shown that the metamaterial may be engineered to provide a close approximation to the parabolic dispersion relation required by the Talbot effect for perfect imaging. These findings are then applied to the multimode region and access waveguide tapers of a multi-slotted waveguide multimode interference coupler with slots either in the transverse direction or longitudinal direction. A novel polarisation beam splitter exploiting the anisotropy provided by a longitudinally slotted structure is demonstrated by simulation. The thesis describes the design, verification by simulation and layout of a photonic integrated circuit containing metamaterial waveguide test structures. The test and measurement of the fabricated chip and the analysis of the data is described in detail. The experimental results show good agreement with the theory, with the expected errors due to fabrication process limitations. From the Scanning Electron Microscope images and the measurements, it is clear that at the boundary of the minimum feature size limit, the error increases but still the devices can function.

ransmitted-light coherence-controlled holographic microscope (CCHM) based on an off-axis achromatic and space-invariant interferometer with a diffractive beamsplitter has been designed, constructed and tested. It is capable to image objects illuminated by light sources of arbitrary degree of temporal and spatial coherence. Off-axis image-plane hologram is recorded and the image complex amplitude (intensity and phase) is reconstructed numerically using fast Fourier transform algorithms. Phase image represents the optical path difference between the object and the reference arms caused by presence of an object. Therefore, it is a quantitative phase contrast image. Intensity image is confocal-like. Optical sectioning effect induced by an extended, spatial incoherent light source is equivalent to a conventional confocal image. CCHM is therefore capable to image objects under a diffusive layer or immersed in a turbid media. Spatial and temporal incoherence of illumination makes the optical sectioning effect stronger compared to a confocal imaging process. Object wave reconstruction from the only one recorded interference pattern ensures high resistance to vibrations and medium or ambience fluctuations. The frame rate is not limited by any component of the optical setup. Only the detector and computer speeds limit the frame rate. CCHM therefore allows observation of rapidly varying phenomena. CCHM makes the ex-post numerical refocusing possible within the coherence volume. Coherence degree of the light source in CCHM can be adapted to the object and to the required image properties. More coherent illumination provides wider range of numerical refocusing. On the other hand, a lower degree of coherence makes the optical sectioning stronger, i.e. the optical sections are thiner, it reduces coherence-noise and it makes it possible to separate the ballistic light. In addition to the ballistic light separation, CCHM enables us to separate the diffused light. Multi-colour-light

La construction d’un NSOM, dans ce manuscrit de thèse, est décrite en détail. Lacombinaison du système NSOM construit avec un interféromètre est proposée afin d’accéderà des mesures de phase, à la fois de ultra-haute sensibilité mais également de très granderésolution spatiale. Le nom de l’instrument développé est un interferomètre optique àbalayage en champ proche (NSOI, pour l’acronyme en anglais). Le principe est basé surl’utilisation d’un diapason accordable en cristal de quartz, sur lequel se trouve une pointe,afin de sonder le matériau étudié. La mesure de la force de cisaillement de la pointe sondeau voisinage de la surface permet d’assurer la régulation et la stabilité de la distance depositionnement de la pointe par rapport à la surface considérée. Le dispositif est construit encombinant différents éléments électroniques pilotés par un logiciel développé en langageLab-VIEW. Le bruit de la mesure en NSOI est supprimé par un calcul simple basé sur lathéorie de l’optique ondulatoire et des interférences associées. Le système permet deréaliser des mesures optiques en champ proche ainsi que la détermination en hauterésolution de la phase du champ optique. L’échantillon SNG01 (l’un des réseaux utilisés pourcaractériser notre microscope à balayage en champ proche), ainsi que des disques optiques(CD, DVD and disques blu-ray) ont été utilisés pour tester la faisabilité et les performancesde notre système.Dans ce manuscrit de thèse, le graphène et les monocouches de MoS2 sont étudiés. Nous montrons qu’une épaisseur à l’échelle atomique peut être résolue par notresystème NSOI, avec l’utilisation de l’algorithme de suppression du bruit de mesure. Lesjoints de grain du graphène sont observés à grande échelle, via la technique d’imagerie parcollection en champ proche et par la réalisation de cartographies de phase. En particulier,les tensions internes à une couche de graphène sont observées, uniquement dans le casd’une imagerie de phase. / In this thesis, near-field scanning optical interferometry (NSOI), which combinesNSOM with interferometer, is proposed for the phase measurement. The shear-forcedetection scheme is applied for distance regulation. The hardware of the systemis constructed by combining various electronic devices, and the operating softwareis coded by LabVIEW. Unwanted background signal is removed by simple calculationbased on interference theory. By using this, the near-field optical measurementand the ultra-sensitive phase investigation of nano-materials are performed. 2D materialssuch as graphene and monolayer MoS2 are investigated. It is shown thatatomic-scale thickness can be resolved by the NSOI. Especially, the grain boundariesof graphene and the seed of MoS2 can be found by phase detection. In addition,direct laser writing (DLW) on silver-containing glass is observed by using NSOM,and NSOI. For the first time, the writing threshold is correlatively observed in thefluorescence imaging and the near-field phase image.

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Ultraprecision single point diamond turning is required to produce parts with sub-nanometer surface roughness and sub-micrometer surface profiles tolerances. These parts have applications in the optics industry, where tight form accuracy is required while achieving high surface finish quality. Generally, parts can be polished to achieve the desired finish, but then the form accuracy can easily be lost in the process rendering the part unusable. Currently, most mid to low spatial frequency surface finish errors are inspected offline. This is done by physically removing the workpiece from the machining fixture and mounting the part in a laser interferometer. This action introduces errors in itself through minute differences in the support conditions of the over constrained part on a machine as compared to the mounting conditions used for part measurement. Once removed, the fixture induced stresses and the part’s internal residual stresses relax and change the shape of the generally thin parts machined in these applications. Thereby, the offline inspection provides an erroneous description of the performance of the machine. This research explores the use of a single, high resolution, capacitance sensor to quickly and qualitatively measure the low to mid spatial frequencies on the workpiece surface, while it is mounted in a fixture on a standard ultraprecision single point diamond turning machine after a standard facing operation. Following initial testing, a strong qualitative correlation exists between the surface profiling on a standard offline system and this online measuring system. Despite environmental effects and the effects of the machine on the measurement system, the capacitive system with some modifications and awareness of its measurement method is a viable option for measuring mid to low spatial frequencies on a workpiece surface mounted on an ultraprecision machine with a resolution of 1nm with an error band of ±5nm with a 20kHz bandwidth. / Thesis / Master of Applied Science (MASc)