229 research outputs found
High-accuracy Casimir-Polder force calculations using the Discontinuous Galerkin Time-Domain method
We describe a numerical time-domain approach for high-accuracy calculations
of Casimir-Polder forces near micro-structured materials. The use of a
time-domain formulation enables the investigation of a broad range of materials
described by advanced material models, including nonlocal response functions.
We validate the method by a number of example calculations for which we
thoroughly investigate the convergence properties of the method, and comparing
to analytical reference calculations, we find average relative errors as low as
a few parts in a million. As an application example, we investigate the
anisotropy-induced repulsive behavior of the Casimir-Polder force near a sharp
gold wedge described by a hydrodynamic Drude model.Comment: 17 pages, 11 figure
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Nanostructured In3SbTe2 antennas enable switching from sharp dielectric to broad plasmonic resonances
Phase-change materials (PCMs) allow for non-volatile resonance tuning of nanophotonic components. Upon switching, they offer a large dielectric contrast between their amorphous and crystalline phases. The recently introduced “plasmonic PCM” In3SbTe2 (IST) additionally features in its crystalline phase a sign change of its permittivity over a broad infrared spectral range. While optical resonance switching in unpatterned IST thin films has been investigated before, nanostructured IST antennas have not been studied, yet. Here, we present numerical and experimental investigations of nanostructured IST rod and disk antennas. By crystallizing the IST with microsecond laser pulses, we switched individual antennas from narrow dielectric to broad plasmonic resonances. For the rod antennas, we demonstrated a resonance shift of up to 1.2 µm (twice the resonance width), allowing on/off switching of plasmonic resonances with a contrast ratio of 2.7. With the disk antennas, we realized an increase of the resonance width by more than 800% from 0.24 µm to 1.98 µm while keeping the resonance wavelength constant. Further, we demonstrated intermediate switching states by tuning the crystallization depth within the resonators. Our work empowers future design concepts for nanophotonic applications like active spectral filters, tunable absorbers, and switchable flat optics
Intact regulation of muscle expression and circulating levels of myokines in response to exercise in patients with type 2 diabetes
Exercise induction of key transcriptional regulators of metabolic adaptation in muscle is preserved in type 2 diabetes
X-ray fluorescence (XRF) fingerprinting of Palaeogene deposits in Denmark
In this study, we test if cost-efficient X-ray fluorescence (XRF) analyses can be used to fingerprint Palaeogene clay and marl deposits in Denmark. A total of 67 samples from key sites in Denmark have been analysed. Our preliminary results indicate that it is possible locally within 10–30 km to distinguish between most of the Palaeogene units, but on a regional scale across Denmark, the units are not unique, and this probably reflects variations in clay mineralogy, grain size and calcareous content. Accordingly, we suggest that a comprehensive reference database is now needed if the full potential of the method is to be utilised, and this will ultimately result in more reliable geological models
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