Beschreibung
This thesis focuses on a means of obtaining, for the first time, full electromagnetic imaging of photonic nanostructures. The author also develops a unique practical simulation framework which is used to confirm the results. The development of innovative photonic devices and metamaterials with tailor-made functionalities depends critically on our capability to characterize them and understand the underlying light-matter interactions. Thus, imaging all components of the electromagnetic light field at nanoscale resolution is of paramount importance in this area. This challenge is answered by demonstrating experimentally that a hollow-pyramid aperture probe SNOM can directly image the horizontal magnetic field of light in simple plasmonic antennas - rod, disk and ring. These results are confirmed by numerical simulations, showing that the probe can be approximated, to first order, by a magnetic point-dipole source. This approximation substantially reduces the simulation time and complexity and facilitates the otherwise controversial interpretation of near-field images. The validated technique is used to study complex plasmonic antennas and to explore new opportunities for their engineering and characterization.
Autorenporträt
Denitza Denkova completed her Bachelor (2008) and Master (2010) studies in Physics at Sofia University, Bulgaria. During her studies she also worked part-time as an engineer at Melexis, a microelectronics company. In a joint project between these institutions she studied specific malfunctions in microelectronics circuits via various structural, optical and electrical characterization techniques, including the development of a cathodoluminescence add-on to a scanning electron microscope. Denitza then moved to KU Leuven, Belgium to further develop her interest in nanoscale characterization as a PhD. There she developed and applied a novel approach for imaging the magnetic field of light with nanoscale resolution, in the context of characterization of plasmonic and metamaterial devices.
