Biography:

Albert Polman is scientific group leader at the NWO-Institute AMOLF in Amsterdam, the Netherlands, and professor of Photonic Materials for Photovoltaics at the University of Amsterdam. Polman’s research group studies electron-light-matter interactions in nanophotonic systems using cathodoluminescence spectroscopy. His group also studies nanoscale light management in photovoltaics to realize high-efficiency solar cells with improved functionality and designs and fabricates optical metasurfaces for analog optical information processing. Polman has won several awards for his work, is member of the Netherlands Academy of Arts and Sciences and was awarded three ERC Advanced Grants for his research. Polman is co-founder of Delmic BV that brings an instrument for cathodoluminescence spectroscopy on the market that was developed in his group.

LECTURE: "Cathodoluminescence microscopy"

I will review the instruments, physical mechanisms and applications of cathodoluminescence microscopy. I will describe coherent excitation of plasmonic and dielectric nanostructures and materials and the electrodynamic electron-matter coupling model. I will also describe incoherent excitation processes in semiconductors, the collision cascade and interaction volume. I will then describe the CL instrument, in which a SEM/TEM is integrated with light outcoupling and analysis systems and how the emitted cathodoluminescence is analyzed (spectrum, angle-dependence, polarization, time-dependence, photon correlations). I will end with a discission of the newest trends in time-resolved CL spectroscopy using ultrafast photo-emission SEM-CL and pump-probed SEM-CL. Throughout the lecture I will shows characteristic examples of the use of CL in materials analysis and how they are based on our growing understanding of electron-light-matter interactions.

TALK: "Shaping the interplay between free electrons and light with optical metasurfaces"

In this work, we explore control over the interplay between free electrons and light by tailored optical near fields using optical metagratings. We use angle-resolved cathodoluminescence spectroscopy to determine the dispersion of broadband Smith-Purcell radiation generated by 5-30 keV electrons. We also demonstrate a fiber-coupled metagrating to collect the electron-induced radiation; a geometry that could also serve for the reverse process: to demonstrate Photon-induced Near-field Electron Microscopy (PINEM) in the SEM. From the angle-resolved data we find dispersive Smith-Purcell bands generated in vacuum as well as in the fiber and observe a Fano resonance created by the interference of a broadband incoherent radiation band with the metagrating. Finally, we present a chirped metagrating designs that serve as a metalens to focus the Smith-Purcell radiation and present a novel metasurface design for the generation of polarization-controlled CL emission.