Scientific Highlights

Every year, during the winter months, PhD students of the Swiss Nanoscience Institute take part in the SNI: Nano in the snow PhD school. Currently, as COVID-19 is still omnipresent in our everyday it happened virtually this year and Thomas Mortelmans took part. He said: “It was an exciting day filled with excellent scientific content from a variety of research fields; ranging from quantum physics, to protein engineering and drug delivery. During these events, the interdisciplinary of SNI is nicely highlighted and the benefit of joined research projects across scientific disciplines can be seen.”

Thomas gave an interdisciplinary introduction to the field of microfluidics and was awarded with the prize of best talk.

The compounds known as ‘pyrazinacenes’ are simple, stable compounds that consist of a series of connected nitrogen-containing carbon rings. They are suitable for applications in electrochemistry or synthesis, as the researchers describe in the science journal Communications Chemistry. They were first designed, synthesized and chemically characterized in solution by the Hill team and carefully investigated by Scanning Tunneling Microscopy and Surface Chemical Analysis. The compounds have been shown to reversibly release and accept electrons and arrange themselves differently depending on the oxidation state. Interestingly, the oxidation and reduction reactions of the pyrazinacenes are not only affected by a chemical impulse, but can also be stimulated by light so they can be considered photo-redox active.

Thomas A. Jung has been elected as a delegate of the Associate Members of the European Physical Society. As a member he shall contribute to the reviewing of the activities of the Society, the annual accounts and to the discussion of future priorities and new activities.

Single particle studies play an important role in understanding their physical and chemical properties. Electrostatic trapping is on one such robust method that allows for a contact-free high-throughput single nanoparticle trapping in an aqueous environment in a nanofluidic device. However, finding an optimum design solution for stiffer single particle trapping for different particles is a cumbersome process. This work presents all crucial geometrical parameters required to tune the trapping efficiency of the device, and their impact. Furthermore, the work enables to quickly identify and optimize nanofluidic devices design for stronger single particle confinement using numerical simulations, saving the massive experimental time required for device optimization.

During the past decade, scientists have put high effort to achieve sub-10 nm resolution in X-ray microscopy. Recent developments in high-resolution lithography-based diffractive optics, combined with the extreme stability and precision of the PolLux and HERMES scanning X-ray microscopes, resulted now in a so far unreached resolution of seven nanometers in scanning soft X-ray microscopy. Utilizing this highly precise microscopy technique with the X-ray magnetic circular dichroism effect, dimensionality effects in an ensemble of interacting magnetic nanoparticles can be revealed.

Ricarda Nebling, PhD student at LMN, received a prize at the SPIE Extreme Ultraviolet Conference 2020 for her contribution: “Effects of the illumination NA on EUV mask inspection with coherent diffraction imaging”.

In a joint research effort, an international team of scientists lead by Emmanuelle Jal (Sorbonne Université) performed a time-resolved experiment at the FERMI free-electron laser to disclose the dynamic behavior of two magnetic element of a compount material in only one snapshot. The X-ray Optics and Applications group developed a dedicated optical element for this experiment that is usable with two different photon energies (colors) simultaneously.

In a joint research effort, an international team of scientists lead by Prof. Giovanni de Ninno (University of Nova Gorica, Elettra Sincrotrone Trieste) now demonstrated that an OAM-dependent dichroic effect can be observed on photoelectrons. The photoelectrons are released from a sample of He atoms that is excited by the strong extreme ultraviolet light pulses from the FERMI free electron laser, whereas the orbtial momentum is imprinted with an intense infrared laser pulse. The X-ray Optics and Applications group of PSI supported the team with their experience in the creation of OAM beams and during the experiments.

Our research on multifocus off-axis zone plates was accepted in “Optica”, the highest impact journal of the Optical Society of America. In the paper we report on different ways to combine focusing and beam-splitting functionalities in one single optical element.