Defence of dissertation in the field of applied physics, M.Sc. Markus Nyman

Title of the doctoral thesis is "Nanophotonic control of optical emission, propagation, and all-optical modulation"
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Nanotechnology is an important element in modern optics and photonics, because it allows us to control light effectively and in new ways. Materials made of nanostructures can be created to suit particular applications, and they can have extraordinary optical properties. For example, one can design a nanomaterial with a negative or zero refractive index. This dissertation focuses on the study and design of optical nanomaterials for the purpose of controlling the emission and propagation of light. The main aim of the research is to devise better ways to design light sources and other optical components that utilize nanomaterials. Light-matter interaction can be complex in these systems, requiring the development of new methods to study it.

The thesis presents an approach for theoretical and computational modelling of optical emission in nanomaterials, based on so-called wave parameters. Materials of special interest in this work have optical properties that depend on the way light is passing through the material. The theoretical and experimental research reveals interesting phenomena that have potential applications in optics-based sensors and efficient light sources. The thesis also develops a new kind of nanomaterial-based wave plate, an optical component that is used to modify the polarization of light. The wave plate is based on the strong birefringence of a metal-polymer nanostructure. The structure is very thin, making it possible to integrate it into small optical devices.

Finally, the dissertation examines all-optical modulation. Modulation is the act of making a signal carry information. To make optical data processing as fast as possible, it is desirable to exchange information between optical signals without involving intermediate electronics. Such all-optical modulation requires nonlinear optical interaction between the signals. The thesis presents a method of all-optical modulation that has the elusive combination of strong nonlinearity and high modulation speeds. A method for detecting very fast optical signals using the same system is also presented, and both methods are verified experimentally at sub-picosecond time scales. This work offers alternatives to more traditional methods of modulation and detection, and the results may prove useful in optical communications and data processing, as well as in the study of ultrafast physical phenomena.

Opponent is Professor Alexandre Dmitriev, University of Gothenburg, Sweden

Custos is Professor Matti Kaivola, Aalto University School of Science, Department of Applied Physics

Contact details of the doctoral candidate: Markus Nyman, [email protected]

The public defence will be organised via Zoom. Link to the event

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The dissertation is publicly displayed 10 days before the defence in the publication archive Aaltodoc of Aalto University

Electronic dissertation

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