Optical fibres are the invisible backbone of modern communication, carrying data for the internet, mobile networks, and countless everyday technologies. While silica-based fibres dominate the field today, they are limited when it comes to broader infrared applications and new uses, such as advanced sensing.
In her research, Iuliia Kraskowski explored how adding silver oxide and forming silver nanoparticles in glass can overcome some of these limitations. She worked with phosphate- and tellurite-based glasses doped with erbium – a rare-earth element widely used in optical amplification.
One of her key findings was that silver significantly increases the thermal stability of phosphate glasses, making it possible to draw them into optical fibres. In tellurite glasses, controlled heat treatment led to the formation of silver nanoparticles, which modified and, in some cases, enhanced the luminescence of the materials in both the visible and infrared range. In addition, her work showed that replacing sodium with silver in tellurite glasses has the potential to enable the fabrication of planar optical waveguides through ion-exchange processes.
“My research demonstrates that silver can improve both the processing and the performance of optical glasses. These results help to develop future telecommunications and optical sensing devices,” says Kraskowski.
The significance of her doctoral research lies in its potential impact on future photonic technologies. By changing the glass composition and nanostructure, the study opens up new possibilities for developing materials that are not only stable and easy to process but also capable of improved optical performance.
Iuliia Kraskowski carried out her doctoral research within the Faculty of Engineering and Natural Sciences at Tampere University.
Public defence on Wednesday 24 September
The doctoral dissertation of MSc (Tech) Iuliia Kraskowski in the field of physics titled Engineering of thermally stable oxyfluorophosphate and tellurite glasses with enhanced spectroscopic properties for optical waveguide applications will be publicly examined at the Faculty of Engineering and Natural Sciences at Tampere University in auditorium F115 in the Arvo building on the Kauppi campus (address: Arvo Ylpön katu 34, Tampere) on Wednesday 24 September 2025 at 12:00.
The opponents will be Docent Nadia Giovanna Boetti from Fondazione LINKS and Professor Stucchi de Camargo Alvarez Bernardez from Friedrich Schiller University Jena. The Custos will be Professor Laeticia Petit from the Faculty of Engineering and Natural Sciences at Tampere University.