This thesis addresses particular topics in the field of the length metrology for nanometrology. Nanometrology deals with dimensional measurements of micro- and nanostructures with a high spatial resolution. It typically combines a microscope imaging with a precise coordinate measurement, usually capable of nanometre resolution using the state-of-art laser interferometry techniques. The development in this field is driven, among others, by emerging advanced nanotechnologies that demand to push further the capabilities and limits of the interferometric techniques to make the nanometre-level dimensional measurement of nanostructures possible. The principal limitations of current systems are the environmental conditions and especially the fluctuations in the refractive index of air. The theoretical part of this thesis aim at analysis of individual parts of laser interferometer. I oriented myself on the study of their advantages/disadvantages and further also the possibilities of their industrial applications. The second part of the thesis presents my work that focused on the influence of the refractive index of air (RIA) on the measurement uncertainty. I experimentally demonstrated an interferometric system with a self-cancellation RIA fluctuations: a transparent photodetector is used for the measurement of the standing wave along the axis of a passive resonator, where the resonator also serves as a reference for the laser wavelength stabilisation. Another optical arrangement, based on a setup of several Michelson interferometers, represents a combination of an interferometer and a refractometer into a single system. This setup was used to study the behaviour of the ambient airflow with respect to the optical path difference and physical separation of the interferometer’s and refractometer’s path. Based on the experimental results I proposed new arrangements for shape measuring interferometers, which combine length interferometry and a tracking refractometer for the direct compensation of RIA fluctuations with geometrically adjacent optical beams. The results indicate an improvement in RIA fluctuation induced uncertainty by a factor of 100. Third part describes the design and implementation of interferometric systems for specific applications. For the industrial environment I developed a compact interferometric displacement gauge which is designed to allow nanometre level measurement using a simplified interferometer construction. For coordinate measurement of the position of the sample up to six degrees of freedom, I realised a compact modular interferometric system, which represents a unique setup together with a stabilised laser source. To measure the position of the sample in an electron beam writer chamber, I designed and implemented a differential interferometer that works in the near infrared domain and uses a new detection method developed for this system. In the fourth part I describe the realisation of a high-speed interferometer with a differential arrangement, which allows evaluation of high-cycle fatigue in material engineering. This method of studying high-cycle fatigue should be beneficial for both the basic research and the engineering practice.

The aim of this master´s thesis was the measurement of electrical conductivity and dynamic viscosity of the electrolytes. Based on these measurements to verify Walden theorem between measured variables. Electrolytes were used on sulfolane base in combination with propylene carbonate and salt. The thesis also deals with the measuring method of dielectric properties of electrical and optical method with a refractometer. The freezing point of combination of sulfolan and propylene carbonate were determined by cryoscopy.

Analyzing the structure of a single cell based on its refractive index (RI) distribution is a common and valued approach, because it does not require any artificial markers. The RI is an inherent structural marker that can be quantified in three dimensions with optical diffraction tomography (ODT), an inverse scattering technique. This work reviews the theory of ODT and its implementation with an emphasis on single-cell analysis, identifying the Rytov approximation as the most efficient descriptor for light propagation. The accuracy of the reconstruction method is verified with in silico data and imaging artifacts associated with the inverse scattering approach are addressed. Furthermore, an experimental ODT setup is presented that consists of a bright-field microscope, a phase-imaging camera, and an optical trap combined with a microfluidic chip. A novel image analysis pipeline is proposed that addresses image corrections and frame alignment of the recorded data prior to the RI reconstruction. In addition, for a rotational axis that is tilted with respect to the image plane, an improved reconstruction algorithm is introduced and applied to single, suspended cells in vitro, achieving sub-cellular resolution.

The purpose of this work is to test the feasibility of using particle image velocimetry(PIV) for measurements of flow through a porous medium, more specifically in this casea rotating bed reactor S3. The results from experiments preformed can then be usedto validate and improve computational fluid dynamics models. The report presentsdifferent possible combinations of solids and fluids for refractive index matchingand tests some velocity limits of the optical equipment used. PIV appears to be apromising method for measuring flow through a porous medium. The theoreticallimit due to motion blur is an angular velocity of around 3800 RPM, and the actualtested lower bound for this limit is 453 RPM.

Optical properties of bismuth borate are measured for the composition range x Bi2O3 (1-x) B2O3, 0.25 < x < 0.65. The refractive indices increase as the bismuth content is increasing. Also the ultraviolet absorption edge was shown to shift to longer wavelengths. From these measurements a generalized Sellmeier formula was derived. Applying heat treatments to the prepared bismuth borate glasses in order to obtain glass ceramics leads in most cases to surface nucleation. It was proved that dopants increase the number of nucleating sites on the surfaces. On erbium-doped samples absorption and luminescence measurements were made. The Judd-Ofelt analysis revealed comparably high Judd-Ofelt coefficients. All coefficients were shown to decrease as the Bi2O3 content increases. The luminescence at 1550 nm reveals a broad and flat band which is narrowing with the increase in Bi2O3 content. The green upconversion was observed and the temporal behavior of the emission at 550 nm was investigated. The absorption and emission spectra of chromium-doped bismuth borate glasses were measured. On surface crystallized glasses, for x = 0.5 Bi2O3 and high chromium content, luminescence of chromate (CrO2-4) ion doped BiBO3 microcrystals was observed. Strontium barium niobate microcrystals embedded in strontium barium borate matrix were obtained by spontaneous nucleation in the melt and rapid quenching. Optical properties of Pb2B5O9Br based glass were also investigated. The heat treatment applied leads to the formation of small nanocrystals inside the glass.

The master´s thesis deals with the study of optical properties of thin transparent layers on the organic materials (PPV, P3HT, TiO2, DPP) and especially with the determination of dispersion dependences of refractive index of prepared thin layers. In the theoretical part there are described principles of deposition thin layers of the analyzed materials and their properties. In addition, there are also described methods of optical properties measurements (optical and interference microscopy and ellipsometry). The combination of interference microscope with digital camera was used for determination of refractive index. The image analysis was used for the determination of parameters (with help of the software HarFA). The images of thin layers surfaces were analyzed from the side of the metal contact as well as from the side of glass. In conclusion, there are presented results of the refractive index of the thin layers obtained from the measured values.

Beam combining techniques have become an important tool in the design of high-power high-brightness laser systems. Spectral beam combining (SBC) is an incoherent combining technique that does not require phase control of sources, allowing for a stable and robust system. Using SBC, beams from an array of lasers with each element operated at a different wavelength are combined into a single near-diffraction-limited beam with the same aperture using dispersive optical elements. SBC by means of volume Bragg gratings (VBGs) utilizes unique spectral response of VBGs: diffraction efficiency is close to unity when the Bragg condition is satisfied and is close to zero at multiple points corresponding to particular wavelength offsets from Bragg condition. High-efficiency VBGs can be recorded in UV-sensitive photo-thermo-refractive (PTR) glass. Narrow-band reflecting VBGs allow multi-channel SBC with high spectral density of channels. In this dissertation, experimental results of SBC with high spectral density of combined channels in two spectral regions of interest (1064 and 1550 nm) are reported. The behavior of narrow-band VBGs under high-power laser radiation is investigated. A laser system with kW-level output power and near-diffraction-limited divergence of spectrally-combined output beam is demonstrated. The system combines five randomly-polarized Yb-doped fiber lasers with 0.5 nm spectral separation in central wavelengths using narrow-band reflecting VBGs with absolute efficiency of combining > 90%. A novel design of a multi-channel high-power SBC system is suggested. In this approach, a common-cavity is created for all channels such that wavelengths of the sources are passively controlled by the combination of a common output coupler and intra-cavity VBGs which also act as combining elements. Laser wavelengths are automatically selected to match resonant wavelengths of respective VBGs. We report successful demonstration of a passively-controlled SBC system consisting of two amplifiers in a common cavity configuration. A compact and rugged monolithic SBC module based on multiplexed VBGs is introduced. Experimental results of a four-channel implementation of such module are discussed. Modular design of high-power laser systems is suggested with multiple modules arranged in a series. We show that with basic combining parameters achieved up to date, laser systems with 10 kW output power can be constructed using this arrangement. Further scaling to 100 kW power level is discussed.

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