Engineering the interplay between light and matter for optical technologies
Since ancient times, inquisitive minds have been profoundly studying the science of light-matter interaction. This ever-evolving quest gave birth to seminal theories in physics such as ancient corpuscular theory, wave theory, theory of relativity and quantum theory, to name a few. It also shaped our understanding on a broad arena of physical phenomena happening in nature and in the universe ranging from astrophysical occurrences to subatomic processes. Scientific research on light-matter interaction has also resulted in technological advancements such as invention of lasers, telescopes and consumer optical products, which are industrialized and utilized in daily life.
Light-matter interaction at nanoscale
Dutta’s research deals with the light-matter interactions at nanometer scale where the ‘matter’ is photoactive organic molecules, and the ‘light’ is a confined optical energy. Here, confinement refers to increasing the energy density of light within a tight physical volume. To achieve this, M.Sc. Arpan Dutta has utilized various optical nanostructures to trap the light. The interplay between the nanometer sized molecules and the confined light modes is engineered by optimizing the nanostructures, i.e., their geometry, materials, and optical responses.
It has been shown in the last few decades that such an engineered light-matter interaction can modify the chemistry of organic molecules and can even alter the material properties if the interaction is intense enough. In this regard, Dutta’s dissertation provides insights on how optical nanostructures should be developed to attain better confinement of light leading to an effective light-matter interaction, and how such orchestrated interplay can be utilized to influence molecular properties. The latter is crucial to achieve a leap in photo-technologies involving organic materials, like organic optoelectronics or organic light harvesting.
Vanishing borders between physics, chemistry and material science
A part of Dutta's research is related to altering photochemistry by manipulating electromagnetic vacuum fields and is in the realm of ‘polariton chemistry’, an interdisciplinary field within nanoscience, involving physics, chemistry and material science. The vacuum field is a zero-point energy of electromagnetic field, which exists even without light and can still affect the matter. Dutta’s research investigated what happens to a chemical reaction when the molecules are trapped inside such an electromagnetic vacuum field in between the metallic mirrors.
"It is an interesting yet perplexing finding since it shows something different than what was theoretically predicted earlier”, says Dutta.
In an article still under peer-review in a Nature portfolio journal, Dutta along with other researchers from his supervisors Professor Jussi Toppari’s and Professor Gerrit Groenhof’s groups show that strong interaction between a vacuum field and organic molecules can modify the yield of a photochemical reaction.
"Strikingly, instead of slowing down or inhibiting the reaction as the original theories have predicted, the strong light and matter interaction increased the reaction yield”, describes Dutta.
"Despite the fact that our finding is a severe warning about things not being as straightforward as thought, it is still a positive reinforcement to the thriving field of polariton chemistry. By taking the new findings into account, we might find other ways to alter material properties through the interplay between light and matter”, Dutta continues.
All studies included in the thesis were performed in collaboration with other researchers from the Nanoscience Center and were funded by the Academy of Finland.
M.Sc. Arpan Dutta defends his doctoral dissertation "Weak and strong coupling between organic molecules and confined light" on 1.12.2023 at noon. Opponent Professor Karl Börjesson (University of Gothenburg) and Custos Professor Jussi Toppari (Ģֱ). The doctoral dissertation is held in English.
Publishing information
The dissertation "Weak and strong coupling between organic molecules and confined light" can be read on the JYX publication archive:
