"Are you interested in optics? Then, I'll show you optics that you won't forget," This is what Professor Jiří Spousta told Lukáš Zezulka, a bachelor's student of physics, a few years ago. And he was right. Lukáš is now a winner of the Brno Ph.D. Talent scholarship, he calls the nanoworld his home and is currently working on the development of new attachments for electron microscopes.
"We want to develop a new device that would be usable, for example, for battery, semiconductor or general materials research. Its advantage should lie in the combination of various microscopic techniques so that we would be able to examine the material on a very small scale and characterize it at the same time," explains Lukáš Zezulka, a doctoral student from the Faculty of Mechanical Engineering, who also works at CEITEC BUT.
The tools of the Brno-based NenoVision startup can already do something similar. "We are building on their equipment, trying to expand it with the possibility of observing samples with the help of light. At the same time, we want to be able to influence the samples in some way or produce them directly in the device’s chamber. As a result, we could observe the events dynamically during the process itself," adds Zezulka.
When he talks about a very small scale, he means the nanoworld, an area where we operate in dimensions of an order of magnitude lower than the thickness of a human hair. In case a laboratory instrument is to be used in such an environment, it must also be of a very small size. It is no different with the multifunctional tip probe that Lukáš Zezulka and his colleagues are working on. "The ideal outcome is the sharpest possible tip, which we can use to drive over the surface of the sample and thus map its relief. At the same time, the probe should be compatible with an electron microscope so that during a tip-assisted observation it is possible to look at the sample through electrons. And then we would like to create the tip on an optical fibre, which would allow us to either channel light to the sample or collect light from it," explains Zezulka.
The Brno physicists have the ambition to improve optical fibres so that they can conduct, in addition to light, also working gas for the production of nanostructures. "This is associated with the problem of the tip creation, the standard techniques cannot be used for this. We came up with the revolutionary idea that we would make the tips separately outside the optical fibre which would make them replaceable. In their production, we cooperate with IQS nano, using the 3D printing method, specifically two-photon polymerization, which allows printing with very low resolution. This gives us a tip about 250 micrometres long and 150 micrometres wide. The tip is then sharpened by etching in plasma to get to a sharpness within the range of the lower tens of nanometers," says Zezulka.
He likes the laboratory the most.
Although a physical engineer, Lukáš Zezulka is currently working rather on the technical part of things. "At this stage of our development, technology probably predominates, because it consists mainly of work with existing technical equipment. But it is an attempt to use technology in the service of physics," he says. He came across the field he has been working on since his bachelor's degree quite by coincidence. He was looking for a semester project related to optics when Professor Jiří Spousta guided him in this direction. "He told me literally: 'I'll show you a lens you won't forget.' Since then, I've been doing this and I enjoy it very much as it is a creative activity and the topic is constantly developing," recalls Zezulka.
He decided to study physics in high school, but in retrospect, he said he had no idea what to expect. "I thought it would just be a lot of maths, like in high school. But university physics, especially here at the Institute of Physical Engineering, is closely focused on working in the laboratory. And that's the most fun thing about it in the end," he says with a smile.
Lukáš Zezulka received the award in February together with a three-year Brno Ph.D. Talent scholarship. "It allows me to pursue my doctoral studies with much less worries. I don't have to think about whether it would be good to work somewhere one or two days a week and earn money," says Zezulka. In addition to security during his studies, the award is also a great motivation for him. "I think there is something like a snowball effect in science. There is a chance that if you manage to start with such success, other successes could snowball, and at least it gives me the motivation to continue in science further on," he concludes.