The doctoral dissertation in the field of Physics will be examined at the Faculty of Science, Forestry and Technology, Joensuu Campus.
What is the topic of your doctoral research? Why is it important to study the topic?
My thesis covers research on the coherence properties of random electromagnetic beams and pulsed scalar light. Fundamentally all light fields exhibit stochastic behavior, which requires the use of statistical methods for their description. In coherence optics the random field is treated in terms of averaged quantities, which are measurable and whose behavior, e.g., in propagation and interference of light can be predicted. The current work contributes to the foundations and description of optical fields and fosters potential advances in photonics sciences and technology.
What are the key findings or observations of your doctoral research?
Key results are: 1. Introduction of the singular-value decomposition of the coherence matrix for the description of random vectorial beam fields. 2. Illustration of the spatial coherence of electromagnetic beams geometrically with the coherence Poincaré sphere. 3. Cross-spectrally pure and spectrally invariant pulsed fields are generated from partially coherent isodiffracting beams by employing specific optical systems. 4. A reduction formula for cross-spectral purity in the domain of pulsed fields is derived. 5. The electromagnetic temporal degree of coherence is determined using a Michelson interferometer and polarimetric measurements. These are the fundamental contributions of the work which add foundational value to the research on coherence and polarization of light.
How can the results of your doctoral research be utilised in practice?
The results provide new insights and novel methods which advance the research on the coherence characteristics of random light. Foundational research on light fields plays a pivotal role in stimulating the growth of optics and photonics, enabling advances in diverse areas of modern science and technology.
What are the key research methods and materials used in your doctoral research?
The research encompasses primarily theoretical work, involving analytic and numerical calculations. Point 5 above concerning coherence measurements incorporates also experimental work.
The doctoral dissertation of Jyrki Laatikainen, MSc, entitled Coherence in Optical Fields: Novel Constructions and Spectral Effects will be examined at the Faculty of Science, Forestry and Technology, Joensuu Campus. The opponent will be Professor Riccardo Borghi, Roma Tre University, and the custos will be Professor Tero Setälä, University of Eastern Finland. Language of the public defence is English.
