Three-dimensional photonic confinement in imprinted liquid crystalline pillar microcavities

Sv.H. acknowledges financial support by the EPSRC ”Hybrid Polaritonics” Grant (EP/M025330/1). F.W. thanks the Deutsche Forschungsgemeinschaft (DFG) for financial support (WU317/18-1).We demonstrate the feasibility of a thermal imprint technology capable of structuring organic thin films with liquid crystalline properties forming feature sizes on a several micrometer scale. The imprint technique can directly be applied onto a variety of substrates including dielectric mirrors. The so fabricated three-dimensional microcavities have lateral extensions up to 20 µm and heights between 1 and 5 µm. Exemplarily, pillar microcavities were produced wherein three-dimensional photonic confinement is observed by the formation of 0D cavity mode patterns. The imprint technique further favors the formation of hemispherical pillar geometries rather than cylindrical pillars resulting in equidistant mode spacings of transversal cavity modes.PostprintPeer reviewe

Exciton-polariton condensation in organic semiconductor microcavities with hemispherical potential landscapes

Exziton-Polaritonen sind hybride Quasiteilchen, die entstehen durch die starke Kopplung zwischen Halbleiter-Exzitonen und Mikrokavitätsphotonen in einem optischen Resonator. Aufgrund ihres bosonischen Charakters können die Polaritonen Kondensate ausbilden. In dieser Arbeit ist der emittierende organische Halbleiter das fluoreszierende Protein mCherry. Um einen räumlichen Einschluss zu generieren wurden hemisphärische Potentiale genutzt. Durch die Variation der Potentiallandschaft (Linse, Molekül, Kette, Su-Schrieffer-Heeger-Kette und Honigwaben-Gitter) konnten Eigenschaften wie beispielsweise topologisch nicht-triviale Defekte experimentell bei Umgebungstemperatur demonstriert werden. Zusammengefasst beschäftigt sich diese Arbeit mit der Exziton-Polartion Kondensation in unterschiedlichen Potentiallandschaften mit dem organischen Halbleiter mCherry.Exciton polaritons are hybrid quasiparticles that are created by the strong coupling between semiconductor excitons and microcavity photons in an optical cavity. Due to their bosonic character, the polaritons can form condensates. In this work, the emitting organic semiconductor is the fluorescent protein mCherry. Hemispherical potentials were used to create a spatial confinement. By varying the potential landscape (lens, molecule, chain, Su-Schrieffer-Heeger chain and honeycomb lattice), properties such as topological non-trivial defects were experimentally demonstrated at ambient temperature. In conclusion, this work deals with exciton-polarisation condensation in different potential landscapes with the organic semiconductor mCherry

Dirac Cones and Room Temperature Polariton Lasing Evidenced in an Organic Honeycomb Lattice

Abstract Artificial 1D and 2D lattices have emerged as a powerful platform for the emulation of lattice Hamiltonians, the fundamental study of collective many‐body effects, and phenomena arising from non‐trivial topology. Exciton‐polaritons, bosonic part‐light and part‐matter quasiparticles, combine pronounced nonlinearities with the possibility of on‐chip implementation. In this context, organic semiconductors embedded in microcavities have proven to be versatile candidates to study nonlinear many‐body physics and bosonic condensation, and in contrast to most inorganic systems, they allow the use at ambient conditions since they host ultra‐stable Frenkel excitons. A well‐controlled, high‐quality optical lattice is implemented that accommodates light‐matter quasiparticles. The realized polariton graphene presents with excellent cavity quality factors, showing distinct signatures of Dirac cone and flatband dispersions as well as polariton lasing at room temperature. This is realized by filling coupled dielectric microcavities with the fluorescent protein mCherry. The emergence of a coherent polariton condensate at ambient conditions are demonstrated, taking advantage of coupling conditions as precise and controllable as in state‐of‐the‐art inorganic semiconductor‐based systems, without the limitations of e.g. lattice matching in epitaxial growth. This progress allows straightforward extension to more complex systems, such as the study of topological phenomena in 2D lattices including topological lasers and non‐Hermitian optics

Diarrheagenic enteroaggregative Escherichia coli causing urinary tract infection and bacteremia leading to sepsis

We report a case of a 55-year-old immunocompromised female who presented to the emergency department with severe diarrhea and vomiting following travel to the Philippines. Stool bacteriology revealed a mixed infection involving an enteropathogenic Escherichia coli and two distinct strains of enteroaggregative Escherichia coli (EAEC). During hospitalization, urine and blood culture tested positive for one of the diarrheagenic EAEC strains, necessitating urinary catheterization, intensive care, and antimicrobial treatment with trimethoprim-sulfamethoxazole, followed by meropenem. Although known to occasionally cause urinary tract infections, EAEC have not been previously associated with sepsis. Our report highlights the potential of EAEC to cause severe extraintestinal infections

Coherence and Interaction in Confined Room-Temperature Polariton Condensates with Frenkel Excitons

Strong light–matter coupling of a photon mode to tightly bound Frenkel excitons in organic materials has emerged as a versatile, room-temperature platform to study nonlinear many-particle physics and bosonic condensation. However, various aspects of the optical response of Frenkel excitons in this regime remained largely unexplored. Here, a hemispheric optical cavity filled with the fluorescent protein mCherry is utilized to address two important questions. First, combining the high quality factor of the microcavity with a well-defined mode structure allows to address whether temporal coherence in such systems can be competitive with their low-temperature counterparts. To this end, a coherence time greater than 150 ps is evidenced via interferometry, which exceeds the polariton lifetime by 2 orders of magnitude. Second, the narrow line width of the device allows to reliably trace the emission energy of the condensate with increasing particle density and thus to establish a fundamental picture that quantitatively explains the core nonlinear processes. It is found that the blue-shift of the Frenkel exciton–polaritons is largely dominated by the reduction of the Rabi splitting due to phase space filling effects, which is influenced by the redistribution of polaritons in the system. The highly coherent emission at ambient conditions establishes organic materials as a promising active medium in room-temperature polariton lasers, and the detailed insights on the nonlinearity are of great benefit toward implementing nonlinear polaritonic devices, optical switches, and lattices based on exciton–polaritons at room temperature

Representation of bee products in the nutrition of adults in the Czech Republic

Currently at the forefront of people's healthy eating and healthy lifestyle. Bee products are a source of healthy nutrition. In the framework of representation of bee products in the nutrition of adults in the Czech Republic was through a questionnaire addressed a group of 1,086 persons age structure over 18 years old, living permanently in the Czech Republic. It was found that the best known bee products in the adult population include honey (99 %), the second most famous product is the beeswax (93 %), and knowledge of other products gradually decreases in the number of propolis (81 %), royal jelly (77 %) pollen (59 %), bee venom (45 %), bee brood (22 %). The most common honey bee products. Its consumption is 0.6 to 1 kg / person / year, when its consumption rises in interest groups, such as the beekeepers to 1.5 - 5 kg / person / year and more. The most common use of honey is its direct consumption, which is the preferred liquid consistency and type of honey - blossom (nectar) honey