Filetype
Transient dielectric functions with a 120 fs time resolution of Ge, Si, and InP were acquired from 1.7 to 3.5 eV with a femtosecond pump-probe rotating-compensator ellipsometer. The intensity of the pump laser (with 1.55, 3.10, or 4.65 eV photon energy) was adjusted to create an initial near-surface carrier density of 1020 cm-3. In Ge, there is a significant (∼15%) decrease in the E1 and E1 + Δ1 c
The insulator-to-metal transition (IMT) in vanadium dioxide (VO2) can enable a variety of optics applications, including switching and modulation, optical limiting, and tuning of optical resonators. Despite the widespread interest in VO2 for optics, the wavelength-dependent optical properties across its IMT are scattered throughout the literature, are sometimes contradictory, and are not available
When incorporating anisotropic materials, planar microcavities can give rise to exceptional points, i.e. propagation directions along which two otherwise polarization-split photonic modes degenerate in energy and broadening. They are non-Hermitian degeneracies revealing complex-square-root topology and chiral eigenstates. We show computations and experiments on ZnO-based microcavities.
Efficient suppression of reflection is a key requirement for perfect absorption of light. Recently, it has been shown that reflection can be effectively suppressed utilizing a single ultrathin film deposited on metals or polar materials featuring phonon resonances. The wavelength at which reflection can be fully suppressed is primarily determined by the nature of these substrates and is pinned to
We demonstrate that exceptional points exist in fully transparent, optically "effectively" biaxial, anisotropic micro-cavities, fabricated using an uniaxial cavity material with its axis inclined to the Bragg mirror growth direction. This is similar to the existence of singular (optic) axes in absorbing biaxial crystals, but the lack of time reversal symmetry is mediated by the mode broadening, i.
Planar microcavities allow the control and manipulation of spin polarization, manifested in phenomena like the optical spin Hall effect due to the intrinsic polarization mode splitting. Here, we study a transparent microcavity with broken rotational symmetry, realized by aligning the optic axis of a uniaxial cavity material in the cavity plane, giving rise to exceptional points in the dispersion r
(Figure presented.). Six out of seven crystal systems are optically anisotropic and birefringent. We review recent insight that biaxial crystals generally exhibit four singular axes (or exceptional points) which can pairwise degenerate for special cases. Planar anisotropic microcavities are discussed as effectively biaxial systems and we predict exceptional points and demonstrate experimentally pa
We studied the doping efficiency of Al and Ga dopants in (Mg,Zn)O alloys as a function of the growth temperature and post growth annealing times. High-temperature growth results in the highest structural quality and highest electron mobility; the doping efficiency is limited by the dopant's solubility. It was investigated in detail that a low growth temperature is needed to achieve free carrier de
The dielectric function of heteroepitaxial YBiO3 grown on a-Al2O3 single crystals via pulsed laser deposition is determined in the spectral range from 0.03 eV to 4.5 eV by a simultaneous modeling of the spectroscopic ellipsometry and optical transmission data of YBiO3 films of different thicknesses. The (111)-oriented YBiO3 films are nominally unstrained and crystallize in a defective fluorite-typ
Cell-based therapies hold great promise in re-establishing organ function for many diseases, including untreatable lung diseases such as idiopathic pulmonary fibrosis (IPF). However, many hurdles still remain, in part due to our lack of knowledge about the disease-driving mechanisms that may affect the cellular niche and thereby possibly hinder the function of any transplanted cells by imposing th
We address the problem of the correct description of light-matter coupling for excitons and cavity photons in the case of systems with multiple photon modes or excitons, respectively. In the literature, two different approaches for the phenomenological coupling Hamiltonian can be found: Either one single Hamiltonian with a basis whose dimension equals the sum of photonic modes and excitonic resona
We have investigated structural, optical, and electrical properties of MgxZn1-xO:(Al/Ga) thin films in dependence on Mg and Al/Ga concentrations. For this purpose, thin films with two perpendicular, lateral composition gradients, i.e., the Mg composition is varied in one direction whereas the Al/Ga concentration is varied in a perpendicular direction were grown at 600-C by pulsed-laser deposition
We present optical properties in the near-infrared to vacuum-ultraviolet spectral range of hexagonal YMnO3. The high-quality (110)-oriented bulk single crystal was grown by the optical floating zone technique. We have determined the tensor of the dielectric function by means of Mueller matrix ellipsometry in the wide spectral range (0.5-9.15) eV. For the spectral range below 5.4 eV, we present muc
The unprecedented scale of the Covid-19 pandemic has been a challenge for health supply chains around the world. Many international humanitarian organizations have had to ensure the continuity of their already complex development programs, while addressing their supply chain disruptions linked to the pandemic. Process modularity has frequently been advocated as a strategy to mitigate such disrupti
Wine is an important beverage with a long tradition, and its moderate consumption may be considered beneficial for human health. Although there are many studies regarding phenolic compounds in wines, there is a lack of information about antioxidants and phenolic content in South American wines. In this study, 35 South American red wines from four different countries, vintages 2004–2013, purchased
Background: We wanted to evaluate if health care for multiple myeloma (MM) patients is equal in different regions of Sweden. Aim: To study differences in survival for MM depending on health care region and early use of modern treatment. Methods and results: Data from the Swedish Myeloma Register from patients diagnosed between 2008 and 2017 was used. Cohorts were defined by the six healthcare regi
Purpose: Metformin (MF) intake associates with reduced levels of circulating low-density lipoprotein-cholesterol (LDL-C). This has been attributed to the activation of AMPK, which differentially regulates the expression of multiple genes involved in cholesterol synthesis and trafficking. However, the exact mechanism underlying the LDL-C lowering effect of MF remains ambiguous. Methods: MF-treated
Aim To explore whether the acute 30-day burden of COVID-19 on health care use has changed from February 2020 to February 2022. Methods In all Norwegians (N = 493 520) who tested positive for SARS-CoV-2 in four pandemic waves (February 26th, 2020 –February 16th, 2021 (1st wave dominated by the Wuhan strain), February 17th–July 10th, 2021 (2nd wave dominated by the Alpha variant), July 11th–December
We compared vaccine effectiveness (VE) against severe COVID-19 during calendar periods from December 2021 to March 2022 when Omicron BA.1 and BA.2, respectively, were the dominating virus variants in Scania county, Sweden. We used continuous density case-control sampling matched for sex and age, and with further adjustment for differences in comorbidities and prior infection. VE remained relativel
Over the past decades, the growing proliferation of international institutions governing the global environment has impelled institutional interplay as a result of functional and normative overlap across multiple regimes. This article synthesizes primary contributions made in research on institutional interplay over the past twenty years, with particular focus on publications with International En
