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Lateral resolution enhanced interference microscopy using virtual annular apertures
(2023-01-27)
The lateral resolution in microscopic imaging generally depends on both, the wavelength of light and the numerical aperture of the microscope objective lens. To quantify the lateral resolution Ernst Abbe considered an optical grating illuminated by plane waves. In contrast, the Rayleigh criterion holds for two point sources or point scatterers separated by a lateral distance, which are
supposed to emit spherical waves. A portion of each spherical wave is collected by the objective lens and results in an Airy disc ...
Aufsatz
Theoretical study of spin polarization in multiphoton ionization of Xe
(2023-04-21)
Spin polarization in the multiphoton above-threshold ionization of 5p3/2- and 5p1/2-electrons of Xe with intense 395nm, circularly polarized laser pulses, is investigated theoretically. For this purpose, we solve the time-dependent Schrödinger equation on the basis of spherical spinors. We, thus, simultaneously propagate the spin-up and spin-down single-active-electron wave packets, driven by the laser pulses in the ionic potential, which includes the spin–orbit interaction explicitly. The present theoretical results ...
Aufsatz
Role of Nanoimprint Lithography for Strongly Miniaturized Optical Spectrometers
(2021-01-11)
Optical spectrometers and sensors have gained enormous gimportance in metrology and information technology, frequently involving the question of size, resolution, sensitivity, spectral range, efficiency, reliability, and cost. Nanomaterials and nanotechnological fabrication technologies have huge potential to enable an optimization between these demands, which in some cases are counteracting each other. This paper focuses on the visible and near infrared spectral range and on five types of optical sensors (optical ...
Aufsatz
Observation of a Long-lived Electronic Coherence Modulated by Vibrational Dynamics in Molecular Nd³+- Complexes at Room Temperature
(2023-03-23)
Temporally delayed, phase-locked coherent pairs of near IR femtosecond laser pulses were employed to study electronic coherences in molecular Nd³+-complexes at room temperature. Dissolved and solid complexes were studied under a confocal microscope set-up with fluorescence detection. The observed electronic coherence on a few hundred femtoseconds time scale is modulated by additional coherent wave packet dynamics, which we attribute mainly to be vibrational in nature. In future, the complexes may serve as prototypes ...
Aufsatz
Three‑dimensional close‑to‑substrate trajectories of magnetic microparticles in dynamically changing magnetic field landscapes
(2022-12-03)
The transport of magnetic particles (MPs) by dynamic magnetic field landscapes (MFLs) using magnetically patterned substrates is promising for the development of Lab‑on‑a‑chip (LOC) systems. The inherent close‑to‑substrate MP motion is sensitive to changing particle–substrate interactions. Thus, the detection of a modified particle–substrate separation distance caused by surface binding of an analyte is expected to be a promising probe in analytics and diagnostics. Here, we present an essential prerequisite for such ...
Aufsatz
Fabrication of High-Quality Thin Single-Crystal Diamond Membranes with Low Surface Roughness
(2022-10-17)
Certain aspects before and during the fabrication of single-crystal diamond (SCD) membranes are highlighted, which are decisive to obtain high-quality membranes with low surface roughness values around 0.2 nm on a small area scale. In addition to the requirements for the starting material, including a high planarity and a moderate surface roughness, the importance of cleaning processes to minimize particles and impurities before and during the structuring is emphasized. With the help of a planarization procedure, ...
Aufsatz
Experimental quantification of site-specific efficiency of Interatomic Coulombic Decay after inner shell ionization
(2023-03-17)
Interatomic Coulombic Decay (ICD) and related interatomic and intermolecular autoionization mechanisms are ubiquitous decay processes of excited atoms and molecules in an environment. It is commonly accepted that the efficiency of ICD of an ionized atom in a cluster increases with an increasing number of nearest neighbors. Here, we present a method for experimental validation of this assumption by a site-specific and quantitative comparison of ICD and its main competitor, Auger decay, in core-level ionized Kr clusters. ...
Aufsatz
Photoelectron circular dichroism of a model chiral anion
(2022-01-18)
Photoelectron circular dichroism (PECD) in the one-photon detachment of a model chiral anionic system is studied theoretically by the single center method. The computed chiral asymmetry, characterized by the dichroic parameter β1 of up to about ±3%, is in good accord with the first experimental observations of the effect in photodetachment of amino acid anions [P. Krüger and K. M. Weitzel, Angew. Chem., Int. Ed. 60, 17861 (2021)]. Our findings confirm a general assumption that the magnitude of PECD is governed by the ...
Aufsatz
Impact of bias correction on climate change signals over central Europe and the Iberian Peninsula
(2023-07-27)
Vegetation models for climate adaptation and mitigation strategies require spatially high-resolution climate input data in which the error with respect to observations has been previously corrected. To quantify the impact of bias correction, we examine the effects of quantile-mapping bias correction on the climate change signal (CCS) of climate, extremes, and biological variables from the convective regional climate model COSMO-CLM and two dynamic vegetation models (LPJ-GUESS and CARAIB). COSMO-CLM was driven and ...
Aufsatz
Sonication-assisted liquid exfoliation and size-dependent properties of magnetic two-dimensional α-RuCl₃
(2023-04-26)
Originating from the hexagonal arrangement of magnetic ions in the presence of strong spin orbit coupling, α-RuCl₃ is considered as model system for the Kitaev-Heisenberg model. While the magnetic properties of α-RuCl₃ have been studied in bulk single crystals or micromechanically-exfoliated nanosheets, little is known about the nanosheets' properties after exfoliation by techniques suitable for mass production such as liquid phase exfoliation (LPE). Here, we demonstrate sonication-assisted LPE on α-RuCl₃ single ...