TY  - INPR
A1  - Huber, Bernhard
A1  - Pres, Sebastian
A1  - Wittmann, Emanuel
A1  - Dietrich, Lysanne
A1  - Lüttig, Julian
A1  - Fersch, Daniel
A1  - Krauss, Enno
A1  - Friedrich, Daniel
A1  - Kern, Johannes
A1  - Lisinetskii, Victor
A1  - Hensen, Matthias
A1  - Hecht, Bert
A1  - Bratschitsch, Rudolf
A1  - Riedle, Eberhard
A1  - Brixner, Tobias
T1  - Space- and time-resolved UV-to-NIR surface spectroscopy and 2D nanoscopy at 1 MHz repetition rate
N2  - We describe a setup for time-resolved photoemission electron microscopy (TRPEEM) with aberration correction enabling 3 nm spatial resolution and sub-20 fs temporal resolution. The latter is realized by our development of a widely tunable (215–970 nm) noncollinear optical parametric amplifier (NOPA) at 1 MHz repetition rate. We discuss several exemplary applications. Efficient photoemission from plasmonic Au nanoresonators is investigated with phase-coherent pulse pairs from an actively stabilized interferometer. More complex excitation fields are created with a liquid-crystal-based pulse shaper enabling amplitude and phase shaping of NOPA pulses with spectral components from 600 to 800 nm. With this system we demonstrate spectroscopy within a single plasmonic nanoslit resonator by spectral amplitude shaping and investigate the local field dynamics with coherent two-dimensional (2D) spectroscopy at the nanometer length scale (“2D nanoscopy”). We show that the local response varies across a distance as small as 33 nm in our sample. Further, we report two-color pump–probe experiments using two independent NOPA beamlines. We extract local variations of the excited-state dynamics of a monolayered 2D material (WSe2) that we correlate with low-energy electron microscopy (LEEM) and reflectivity (LEER) measurements. Finally, we demonstrate the in-situ sample preparation capabilities for organic thin films and their characterization via spatially resolved electron diffraction and dark-field LEEM.
KW  - Photoemission electron microscopy PEEM
KW  - Low energy electron microscopy LEEM
KW  - Spatially resolved 2D spectroscopy
KW  - Two-color pump-probe spectroscopy
KW  - Time-resolved photoemission electron microscopy
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-191906
SN  - 0034-6748
N1  - This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Review of Scientific Instruments 90, 113103 (2019); https://doi.org/10.1063/1.5115322 and may be found at https://doi.org/10.1063/1.5115322.
ER  - 
TY  - INPR
A1  - Fersch, Daniel
A1  - Malý, Pavel
A1  - Rühe, Jessica
A1  - Lisinetskii, Victor
A1  - Hensen, Matthias
A1  - Würthner, Frank
A1  - Brixner, Tobias
T1  - Single-Molecule Ultrafast Fluorescence-Detected Pump–Probe Microscopy
N2  - We introduce fluorescence-detected pump–probe microscopy by combining a wavelength-tunable ultrafast laser with a confocal scanning fluorescence microscope, enabling access to the femtosecond time scale on the micrometer spatial scale. In addition, we obtain spectral information from Fourier transformation over excitation pulse-pair time delays. We demonstrate this new approach on a model system of a terrylene bisimide (TBI) dye embedded in a PMMA matrix and acquire the linear excitation spectrum as well as time-dependent pump–probe spectra simultaneously. We then push the technique towards single TBI molecules and analyze the statistical distribution of their excitation spectra. Furthermore, we demonstrate the ultrafast transient evolution of several individual molecules, highlighting their different behavior in contrast to the ensemble due to their individual local environment. By correlating the linear and nonlinear spectra, we assess the effect of the molecular environment on the excited-state energy.
KW  - Fluoreszenz
KW  - Ultrafast spectroscopy
KW  - Single-molecule microscopy
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-313485
ER  -