Povilas Jurkšaitis Awarded a PhD for Research into Light-Matter Interactions

Physicist Povilas Jurkšaitis from the FTMC Department of Laser Technologies has been awarded a PhD in Natural Sciences. The title of his doctoral thesis is “Fluorescence Dynamics of Plasmon-Exciton Polaritonic States” (academic  supervisor: Prof. Dr Zigmas Balevičius)

In his dissertation, Povilas investigated polaritons – unusual quasiparticles that emerge when two different physical states begin to behave as a single entity. This occurs when electron oscillations arising on metal surfaces (plasmons) couple very strongly with light-absorbing organic molecules (excitons).

The newly formed states – polaritons – acquire entirely new properties: they can evolve extremely rapidly over time and respond very sensitively to their environment.

“My dissertation examined how these states could be used in the development of next-generation optical biosensors. A significant part of the work was devoted to investigating the lifetime of polaritons and how the light they emit changes over time.

Such studies made it possible to take a ‘closer look’ at our structures and to evaluate the interactions between polaritons and the free excitons present in the same structure. I also analysed how the properties of polaritons change depending on the observation angle, using specialised optical spatial filtering techniques,” explains Jurkšaitis.

According to the scientist, most technologies used in lasers, optical sensors, and communication systems are based on individual excitations – transitions between energy levels that are limited by the intrinsic properties of the material itself. The polaritonic states investigated in the dissertation make it possible to fundamentally modify and control these energy levels, thereby opening the way towards next-generation polaritonic lasers, optical biosensors, and single-photon light sources.

Congratulations to our colleague on earning his PhD, wishing him every success in his future research career!

Povilas Jurkšaitis’ dissertation can be accessed via this link.

Info: FTMC