The doctoral dissertation in the field of Photonics 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?
The topic of my doctoral research is the design, fabrication, and characterization of hybrid waveguide structures, specifically focusing on polymer-titania composites for photonic sensing applications. These hybrid waveguides combine the advantages of both polymers and titanium dioxide. The research is essential because it addresses key challenges in photonics, such as improving light confinement and minimizing signal losses, which are necessary for the development of sensitive, low-cost sensors. These sensors can be used for applications ranging from environmental monitoring to medical diagnostics, where precise measurements of refractive index variations are vital. By improving waveguide performance, this research contributes to enhancing the functionality and scalability of integrated optical systems, paving the way for more efficient and accessible sensing technologies.
What are the key findings or observations of your doctoral research?
The key findings of my doctoral research include the successful development of polymer-titania hybrid waveguides that offer enhanced light confinement and reduced propagation losses, making them highly efficient for photonic sensing applications. The implementation of advanced fabrication techniques allowed precise control over waveguide dimensions. What is particularly valuable and interesting about this research is its potential for real-world applications, particularly in sensors for detecting small changes in refractive index, a required factor in fields like environmental monitoring and medical diagnostics. The successful application of a strip-loaded Mach-Zehnder interferometer for ethanol concentration measurement demonstrated the practical utility of these hybrid waveguides. This research opens the door to low-cost, high-performance sensors that could be used for a wide range of applications, benefiting both the scientific community and the general public.
How can the results of your doctoral research be utilised in practice?
The results of my doctoral research can be utilized in practice by advancing the development of high-performance photonic sensors. The hybrid waveguide I have designed, which combines polymer materials with titanium dioxide, offers an efficient and cost-effective solution for enhancing light confinement and minimizing signal losses in optical systems. These waveguides can be applied in sensing devices for a range of applications. For example, the strip-loaded Mach-Zehnder interferometer developed in this research can be used to precisely measure refractive index changes, such as those caused by the presence of specific substances like ethanol. This potential is vital in fields like biochemical sensing, where detecting trace amounts of substances is important. The technologies and methods explored in this research can lead to the creation of more accessible, robust, and affordable sensors, helping industries and research communities develop new diagnostic tools, improve environmental monitoring systems, and enable more efficient sensing technologies.
What are the key research methods and materials used in your doctoral research?
My doctoral research combined theoretical designs and simulations, experimental fabrication, and characterization to develop and optimize hybrid waveguide structures for photonic sensing applications. The research began with the design and simulation of various photonics components and the optimization of waveguide dimensions for enhanced light confinement and reduced signal loss. Fabrication was carried out using advanced techniques such as atomic layer deposition for precise titanium dioxide thin film deposition and spin coating for polymer layers, enabling control over waveguide dimensions. The fabricated waveguides were then characterized through mode retrieval analysis, end-fire coupling, and propagation loss measurements. Finally, the hybrid strip-loaded Mach-Zehnder interferometer was demonstrated for refractive index sensing, successfully measuring ethanol-water concentrations which demonstrated their practicality.
The doctoral dissertation of Isaac Doughan, MSc, entitled Refractive index sensors using hybrid waveguides: Design, fabrication, and characterization will be examined at the Faculty of Science, Forestry and Technology, Joensuu Campus. The opponent will be Professor Mircea Guina, Tampere University, and the custos will be Professor Matthieu Roussey, University of Eastern Finland. Language of the public defence is English.
For more information, please contact:
Isaac Doughan, isaac.doughan@uef.fi, tel. +358 417 170 808
