Time and place
Thursday, 11 June 2026, at 13:00, Building. 341, Auditorium 23
Principal supervisor
Associate Professor Ada-Ioana Bunea, DTU Nanolab
Co-supervisor
Professor Rafael Taboryski, DTU Nanolab
Associate Professor Marco Beleggia, DTU Nanolab
Associate Professor Andrei Laurynenka, Department of Electrical and Photonics Engineering
Assessment committee
Senior Researcher Radu Malureanu, DTU Electro
Professor Duncan Sutherland, Aarhus University
Researcher Thomas LaGrange Institute of Physics, EPFL, Switzerland
Moderator at defence
Associate Professor Paul Kempen, DTU Nanolab
Abstract
Errors coming from electromagnetic lenses have proved difficult to handle ever since
the invention of the electron microscope in 1931. This PhD project titled Fabrication
and characterization of adaptive phase plates for electron optics explores a new
approach to correcting these errors by taking inspiration from light optics.
The thesis describes different designs of microchips called phase plates, which can be
used to correct for spherical aberrations inside a transmission electron microscope.
The working principle of the proposed phase plates is that they can create an
electromagnetic field which negates the intrinsic error coming from the microscope’s
electromagnetic lenses. The thesis describes in detail how such phase plates can be
created, evaluating the feasibility of different technologies and processing. Finally, the
functionality of the fabricated phase plates is characterized and compared to
predictions from simulations.
Throughout the PhD project, four fabrication process flows were established, all of
which were used to successfully fabricate functional phase plates. Characterization of
the phase plates showed the generation of custom electromagnetic fields in line with
those predicted by simulations. However, the fabricated devices need to be redesigned
for integration into electron microscopes.
While more work is still needed for producing phase plates ready to be implemented
into electron microscopes, this PhD project has laid the groundwork for phase plates
and their future use for spherical aberration correction in electron microscope
environments. Successful implementation of future iterations has the potential to boost
the quality of electron microscopy images, particularly in terms of image sharpness
and contrast.
