Termine / Veranstaltungen

MBI Seminar: “Towards attosecond imaging at the nanoscale using extreme ultraviolet high harmonic sources”

Freitag, 26. August 2022 // 13.00

Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie

Max-Born-Straße 2a, 12489 Berlin
Max Born Hall

Dr. Jan Rothhardt | Helmholtz Institute Jena & Institute of Applied Physics

Ultrafast lasers allow generating extremely short attosecond pulses in the extreme ultraviolet region via high harmonic generation. While the ultrashort pulse duration enabled groundbreaking spectroscopic studies of ultrafast electron dynamics on their fundamental attosecond time scales, the short wavelength and the excellent spatial coherence enables imaging with nanoscale spatial resolution.

In my talk, I will present our recent achievements in the latter field, namely achieving 16 nm spatial resolution, quantitative amplitude and phase contrast as well as chemical mapping of a semiconductor device on the nanoscale. These results have been enabled by combining a highly- stable, high photon-flux, table-top EUV source with an interferometrically stabilized ptychography setup, structured EUV illumination and advanced phase-retrieval algorithms.

In a second part I will discuss the challenges of combining high spatial and temporal resolution in ultrafast pump-probe imaging experiments and present a novel approach to deal with the large spectral bandwidth of attosecond pulses, which usually hinders high resolution coherent diffraction imaging. I will present our novel broadband diffractive imaging scheme, which combines multiple-reference wave holography, directional Fourier-filters and a broadband phase retrieval algorithm to retrieve a monochromatic high-resolution image.

In a proof of principle experiment, we demonstrate a spatial resolution of 34 nm (2.5 times the illumination wavelength of 13.5 nm) in combination with a spectral bandwidth supporting a Fourier limited pulse duration of only 380 as. This paves the way for an ultrafast view on nanoscale dynamics e.g. ultrafast charge transfer or ultrafast spin currents being relevant for Petahertz electronics and future data storage.