We present an electrically controlled photonic bandgap fiber device obtained by infiltrating the air holes of a photonic crystal fiber (PCF) with a dual-frequency liquid crystal (LC) with pre-tilted molecules. Compared to previously demonstrated devices of this kind, the main new feature of this one is its continuous tunability due to the fact that the used LC does not exhibit reverse tilt domain defects and threshold effects. Furthermore, the dual-frequency features of the LC enables electrical control of the spectral position of the bandgaps towards both shorter and longer wavelengths in the same device. We investigate the dynamics of this device and demonstrate a birefringence controller based on this principle.

In this paper we propose a novel hybrid optical plasmonic Vivaldi antenna for operation in the standard C telecommunication band for wavelengths in the 1550 nm range. The antenna is fed by a silicon waveguide and is designed to have high gain and large bandwidth. The shape of the radiation pattern, with a main lobe along the antenna axis, makes this antenna suitable for point-to-point connections for inter- or intra-chip optical communications. Direct port-to-port short links for different connection distances and in a homogeneous environment have also been simulated to verify, by comparing the results of a full-wave simulation with the Friis transmission equation, the correctness of the antenna parameters obtained via near-to-far field transformation.

There is the urgent need to study the effects of immunomodulating agents as therapy for Covid-19. An observational, cohort, prospective study with 30 days of observation was carried out to assess clinical outcomes in 88 patients hospitalized for Covid-19 pneumonia and treated with canakinumab (300 mg sc). Median time from diagnosis of Covid-19 by viral swab to administration of canakinumab was 7.5 days (range 0–30, IQR 4–11). Median PaO2/FiO2 increased from 160 (range 53–409, IQR 122–210) at baseline to 237 (range 72–533, IQR 158–331) at day 7 after treatment with canakinumab (p < 0.0001). Improvement of oxygen support category was observed in 61.4% of cases. Median duration of hospitalization following administration of canakinumab was 6 days (range 0–30, IQR 4–11). At 7 days, 58% of patients had been discharged and 12 (13.6%) had died. Significant differences between baseline and 7 days were observed for absolute lymphocyte counts (mean 0.60 vs 1.11 × 109/L, respectively, p < 0.0001) and C-reactive protein (mean 31.5 vs 5.8 mg/L, respectively, p < 0.0001).Overall survival at 1 month was 79.5% (95% CI 68.7–90.3). Oxygen-support requirements improved and overall mortality was 13.6%. Confirmation of the efficacy of canakinumab for Covid-19 warrants further study in randomized controlled trials.

A 3D full-vectorial Beam Propagation Method is successfully applied to compute both the propagation constants and the modal profiles in high-contrast silica-air index-guiding Photonic Crystal Fibers. The approach is intrinsically suited to investigate longitudinally varying structures or propagation and polarization effects, which are of practical interest for advanced optical applications. As an example we model a dual-core coupler, showing that efficient polarization preserving coupling can be expected.

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