Five ARCNL PhD students defend their theses in one month

Within one month, five ARCNL PhD students successfully defended their theses. Congratulations to Doctors Dion Engels, Karl Schubert, Fengling Zhang, Falco Bijloo and Nick Feldman!

Dion Engels

Dion Engels did his PhD in the group of Oscar Versolato, and defended his thesis at Vrije Universiteit (VU) Amsterdam on November 26. Dion’s thesis is titled “Solid-state-laser-driven vaporization and ionization of tin.” In it, he details his findings on both the physics of these processes, and tin vapor’s potential as a source of extreme ultraviolet (EUV) light for nanolithography. Dion originally started in Oscar’s group as a MSc student, and his thesis project then turned out to be the starting point for his PhD research! Want to read more about Dion’s work? Have a look at this previous news item about vaporizing tin.

Karl Schubert

Karl Schubert conducted his PhD research on laser-liquid tin interactions, in the group of Oscar Versolato. He defended his thesis, titled “Laser-Induced Modulation, Vaporization, and Plasma Formation of Free-Flying Liquid Tin Sheets,” at VU Amsterdam on December 9. During his PhD, Karl studied how thin, free-flying sheets of liquid tin react to short laser pulses – a key step in improving EUV generation. He showed that the sheet’s thickness and the laser’s intensity determine how long it takes for the tin sheet to locally evaporate and turn into plasma. He also found clear but mysterious ripple patterns: concentric rings at low power and additional twisting patterns at higher power. These results reveal part of how liquid tin sheets behave and open new questions for the team to explore.

Fengling Zhang

Fengling Zhang did her PhD research on lensless imaging using UV light, supervised by Stefan Witte and Kjeld Eikema. Her technique uses computational imaging to reconstruct images from the diffraction of light as it passes through the sample. Not only did she use this to study the nanoscale structure of a sample, but also to identify unknown materials in different sample layers. This development could be useful to the semiconductor industry as well as for use in medical research. Fengling successfully defended her thesis, titled “Methods and Applications of Extreme Ultraviolet Multi-Wavelength Ptychography in Nanoscale Imaging,” at VU Amsterdam on December 11.

Nick Feldman

Nick Feldman defended his thesis, titled “Optical metasurfaces for information efficient nanoscale metrology,” on December 17 at the University of Amsterdam. He did his PhD research as a joint AMOLF-ARCNL PhD candidate in the groups of Lyuba Amitonova and Femius Koenderink (AMOLF). Nick’s project focused on metasurfaces, which are artificial surfaces made of nanoscale structures, and how they can be used as advanced sensors by converting tiny details into measurable light signals. Nick’s work also shows how shaping the incoming light, together with smart metasurface design, improves measurement accuracy and reliability. Want to learn more about Nick’s research? Check out this previous news item on metasurface sensors.

Falco Bijloo

Falco Bijloo did his PhD in the groups of Peter Kraus and Femius Koenderink (AMOLF), as part of the AMOLF-ARCNL joint PhD program. His thesis explores how resonant metasurfaces can be used for nonlinear optical metrology by exploiting enhanced harmonic generation (light emitted at multiples of the original frequency). This allows small structural changes to be detected with high sensitivity, for example in semiconductor manufacturing applications. Falco successfully defended his thesis, titled “Dynamic nonlinear light control and metrology with resonant metasurfaces,” at the University of Amsterdam on December 17.