Ellipsometry used in internal reflection mode exhibits enhanced thin film sensitivity if operated close to surface plasmon resonance conditions. Compared to conventional ellipsometry, the changes in the ellipsometric parameter Δ are several orders of magnitude larger. Here, the origin of this large sensitivity is discussed by analysing thin film approximations of the complex reflectance ratio. It is found that the thickness sensitivity in Δ is proportional to the inverse of the difference between the intrinsic and the radiation-induced damping of the surface plasmons.

Total internal reflection ellipsometry (TIRE) is used to study adsorption of human serum albumin and fibrinogen on thin gold films. TIRE shows very high sensitivity for protein monolayers adsorbed on metal surfaces when surface plasmon resonance effects are utilized. The measured data, expressed in ellipsometric angles ψ and Δ are of several orders of magnitude larger in comparison with those from similar experiments performed with traditional ellipsometry. TIRE in spectral mode opens a new path for precise studies of organic layers adsorbed on metal surfaces, with a potential for resolving the adsorbed layer microstructure.

A measurement technique based on ellipsometry performed under conditions of total internal reflection is presented here. This technique is called total internal reflection ellipsometry (TIRE). When extended with the surface plasmon resonance effect, TIRE becomes a powerful tool for monitoring protein adsorption on thin metal films. A brief description of TIRE is presented here together with some examples of measurement system setups. Two examples of applications are included, followed by a short presentation of possible future applications of TIRE.

This thesis summarizes the work performed on the development and implementation of the optical measurement technique called total internal reflection ellipsometry (TIRE).

The TIRE principle is based on spectroscopic ellipsometry performed under conditions of total internal reflection. This configuration is suitable for monitoring and analysis of thin semitransparent films and changes in/on these films due to exposure to various media (liquid or gas). When metal films are used this technique can be further extended with the surface plasmon resonance (SPR) effect forming a measurement method, which allows measurements with very high precision. The main advantages of TIRE are the possibility for measurements in opaque liquids and very good detection limits, both unavailable with the complementary techniques, ellipsometry and SPR, used in their conventional mode.

The measurement principles of ellipsometry and surface plasmon resonance have been known for a long time and these techniques are currently widely used in various areas of science and technology. Furthermore, internal reflection ellipsometry has been reported several years ago and possibilities offered by this technique have been discussed by several scientists. However, so far there has been no attempt to give a more comprehensive report containing the combination of theoretical aspects, technical development and practical applications all-in-one. Therefore, the main goal of this work was to give some deeper insight into the TIRE technique by focusing on the following aspects: theoretical and mathematical tools used in TIRE and development of the measurement system with its applications. Unfolding the above - the aim of the TIRE project is to review what has been done so far in the area of TIRE and update this with the current results. Included is also developing a set of components of the TIRE measurement system, and understanding the possible technical problems which may show up, with an attempt to resolve them. Finally, the possible applications of the TIRE technique in various areas of science and technology are exemplified, with focus on the advantages over the currently used techniques.

The TIRE technique is suitable for monitoring of adsorption/ desorption of molecules from various liquid/gas media on the surfaces of the material playing the role of the substrate, as well as for studying the material itself. Within the TIRE project three types of applications have been studied. The first was in situ studies of protein adsorption on thin metal films, with use of SPR extended TIRE. The information obtained was more precise and complete than usually obtainable from SPR and conventional ellipsometry. With appropriate technical setup there is a potential to resolve the morphology of adsorbed multi-layered protein structures with TIRE. The behaviour of proteins on metals is of great importance in many areas of bio-sciences, including medicine (e.g. implants in the human body). The other two applications studied were more technical, with possible industrial relevance: adsorption and subsequent cleaning of substances from milk (useful i.e. for pipeline monitoring in the diary industry) and studies on corrosion on thin copper layers (useful e.g. for circuit board control in the microelectronics industry).

Total internal reflection ellipsometry (TIRE) in spectroscopic mode in the wavelength range 400–1200 nm is employed in situ at a solid/liquid interface for investigation of protein adsorption on thin semitransparent gold films. In this configuration, the surface plasmon resonance phenomenon gives a large enhancement of the thin film sensitivity. Adsorption of a monolayer of the protein ferritin is monitored kinetically in situ and results in a change in the ellipsometric parameter Δ of more than 90° compared to 3° in similar ellipsometric measurements on gold substrates. This large sensitivity demonstrates a potential for sensor applications. The ferritin layer optical function is modeled with a Cauchy dispersion model resulting in a layer thickness of 9.2 nm, in good agreement with the dimension of the ferritin molecules. A transition layer between the protein film and the gold layer is necessary to introduce in the model to account for interactions between the protein layer and the gold film. The large sensitivity of TIRE for thin layers opens up a pathway to analyze in detail the structure of thin protein layers provided that a further development of the experimental setup and the model for the protein layer is carried out.