Theoretical Investigation of Oxazine 170 Perchlorate Doped Polymeric Optical Fiber Amplifier

Optical signal amplification in the waveguiding structure of optical fibers can be used for optical telecommunication systems and new light sources constructions. Organic dyes doped materials are interesting for new applications in polymeric optical fibers technology due to their benefits (efficient fluorescence, high absorption cross section, and easy processing). This article presents a numerical simulation of gain in poly(methyl methacrylate) optical fiber doped by Oxazine 170 Perchlorate. The calculated gain characteristic for the used dye molar concentration (0.2·10-6–1.4·10-6) and pump power (1–10 kW) is presented. The fabricated fluorescent polymeric optical fiber is also shown. The presented analysis can be used for optical amplifier construction based on dye-doped polymeric optical fiber (POF)

Up-conversion luminescence in low phonon heavy metal oxide glass co-doped with Er3+/Ho3+ ions

In this paper, heavy metal oxide glasses co-doped with erbium and holmium ions have been synthesized. Glass composition, based on bismuth and germanium oxides, has been selected in terms of high thermal stability (∆T = 125 °C), high refractive index (n = 2.19) and low maximum phonon energy (hνmax = 724 cm⁻¹). Up-conversion luminescence spectra under the 980 nm laser diode excitation have been observed as a result of radiative transitions within the quantum energy level structures of Er³⁺ and Ho³⁺ ions. Optimization of rare earth ions content has been conducted, the highest emission intensity in the visible wavelength range has been observed in glass co-doped with molar concentration 0.5 Er2O3 / 0.5 Ho2O3

Optical characterization of nano- and microcrystals of EuPO4 created by one-step synthesis of antimony-germanate-silicate glass modified by P2O5

Technology of active glass-ceramics (GC) is an important part of luminescent materials engineering. The classic method to obtain GC is based on annealing of parent glass in proper temperature and different time periods. Generally, only the bulk materials are investigated as a starting host for further applications. However, the effect of an additional heat-treatment process on emission and structural properties during GC processing is omitted. Here, we focus on the possibility of obtaining transparent glass-ceramic doped with europium ions directly with a melt-quenching method. The influence of phosphate concentration (up to 10 mol %) on the inversion symmetry of local environment of Eu3+ ions in antimony-germanate-silicate (SGS) glass has been investigated. The Stark splitting of luminescence spectra and the local asymmetry ratio estimated by relation of (5D0→7F2)/(5D0→7F1) transitions in fabricated glass confirms higher local symmetry around Eu3+ ions. Based on XRD and SEM/EDX measurements, the EuPO4 nano- and microcrystals with monoclinic geometry were determined. Therefore, in our experiment, we confirmed possibility of one-step approach to fabricate crystalline structures (glass-ceramic) in Eu-doped SGS glass without additional annealing process

Single high-dose vitamin D supplementation as an approach for reducing ultramarathon-induced inflammation : a double-blind randomized controlled trial

Purpose: A growing number of studies indicate the importance of vitamin D supplementation for sports performance. However, the effects of a single high-dose vitamin D supplementation on ultramarathon-induced inflammation have not been investigated. We here analyzed the effect of a single high-dose vitamin D supplementation on the inflammatory marker levels in ultramarathon runners after an ultramarathon run (maximal run 240 km). Methods: In the study, 35 runners (amateurs) were assigned into two groups: single high-dose vitamin D supplementation group, administered vitamin D (150,000 IU) in vegetable oil 24 h before the start of the run (n = 16); and placebo group (n = 19). Blood was collected for analysis 24 h before, immediately after, and 24 h after the run. Results: Serum 25(OH)D levels were significantly increased after the ultramarathon in both groups. The increase was greater in the vitamin D group than in the control group. Based on post-hoc and other analyses, the increase in interleukin 6 and 10, and resistin levels immediately after the run was significantly higher in runners in the control group than that in those in the supplementation group. Leptin, oncostatin M, and metalloproteinase tissue inhibitor levels were significantly decreased in both groups after the run, regardless of the supplementation. Conclusions: Ultramarathon significantly increases the serum 25(OH)D levels. Attenuation of changes in interleukin levels upon vitamin D supplementation confirmed that vitamin D has anti-inflammatory effect on exercise-induced inflammation

Spectroscopic properties of erbium-doped oxyfluoride phospho-tellurite glass and transparent glass-ceramic containing BaF2 nanocrystals

The ErF3-doped oxyfluoride phospho-tellurite glasses in the (40-x) TeO2-10P2O5-45 (BaF2-ZnF2) -5Na2O-xErF3 system (where x = 0.25, 0.50, 0.75, 1.00, and 1.25 mol%) have been prepared by the conventional melt-quenching method. The effect of erbium trifluoride addition on thermal, structure, and spectroscopic properties of oxyfluoride phospho-tellurite precursor glass was studied by differential scanning calorimetry (DSC), Fourier-transform infrared (FTIR), and Raman spectroscopy as well as emission measurements, respectively. The DSC curves were used to investigate characteristic temperatures and thermal stability of the precursor glass doped with varying content of ErF3. FTIR and Raman spectra were introduced to characterize the evolution of structure and phonon energy of the glasses. It was found that the addition of ErF3 up to 1.25 mol% into the chemical composition of phospho-tellurite precursor glass enhanced 2.7 µm emission and upconversion. By controlled heat-treatment process of the host glass doped with the highest content of erbium trifluoride (1.25 mol%), transparent erbium-doped phospho-tellurite glass-ceramic (GC) was obtained. X-ray diffraction analysis confirmed the presence of BaF2 nanocrystals with the average 16 nm diameter in a glass matrix. Moreover, MIR, NIR, and UC emissions of the glass-ceramic were discussed in detail and compared to the spectroscopic properties of the glass doped with 1.25 mol% of ErF3 (the base glass)

Tm3+/Ho3+ co-doped germanate glass and double-clad optical fiber for broadband emission and lasing above 2 μm

In this paper, a 2 μm broadband emission under 796 nm laser diode excitation in low phonon energy GeO2-Ga2O3-BaO glass system is co-doped with 0.7Tm2O3/(0.07-0.7)Ho2O3 (mol%). The widest emission band (where the Tm3+ → Ho3+ energy transfer efficiency is 63%) was obtained for 0.7Tm2O3/0.15Ho2O3 co-doped glass from which a double-clad optical fiber was realized and investigated. Optimization of Tm3+/Ho3+ concentration enabled the acquisition of broadband amplified spontaneous emission (ASE) in double-clad optical fiber with a full width at half maximum (FWHM): 377 nm and 662 nm for 3 dB and 10 dB bandwidth, respectively. ASE spectrum is a result of the superposition of (Tm3+: 3H4 →Η3F4) 1.45 μm, (Tm3+: 3F4 → 3H6) 1.8 μm and (Ho3+:5I7 → 5I8) 2 μm emission bands. Hence, highly rare-earth co-doped germanate glass is characterized by a remarkably broader ASE spectrum than silica and tellurite fibers showed promising lasing properties for their further application in tunable and dual wavelength lasers

Glass powder doping of nanocrystal-doped fibres: challenges and results

Incorporating new optical materials as nanocrystals into glass fibres for new functionalities has recently become a hot research topic. Our team (funded by the European FET Open project NCLAS) investigates the introduction of nanoscale laser crystallites into the core of optical fibres using the glass powder doping method. Active Y2O3:Pr3+ nanocrystals (NCs) were prepared via different synthesis methods, and structurally and spectroscopically characterized. After modification of technological parameters, the optimised NCs have been proposed as a luminescence centres to embed into germanate and silicate glass hosts. Glasses were analysed in terms of optical (transmission, refractive index matching to NCs) and thermal (thermal stability, viscosity, thermal expansion coefficient) parameters. Crystallisation issues during fibre drawing were particularly investigated. In a first step, glass powder-NCs mixing techniques and fibre preform preparation were developed. It was shown that temperature cycle profiles including dwell time and heating/cooling ramp rates influenced the glass-NCs properties and can lead to glass crystallisation or NCs dissolution. The sintering investigations pointed out the melting temperature limits to preserve active NCs in the glasses. In germanate glasses, Y2O3:Pr3+ dissolution was noticed at 800°C. In the case of the silicate glass compositions these regions vary from 700°C to 1050°C. The results allowed to select optical fibre drawing conditions performed by the powder-in-tube method. Their distribution uniformity is not yet sufficient, requiring further optimisation of the drawing kinetics.The research project funded by the European FET Open project NCLas: NanoCrystals in Fibre Lasers, Grant agreement number: 82916

Structure and luminescence properties of transparent germanate glassceramics co-doped with Ni2+/Er3+ for near-infrared optical fiber application

An investigation of the structural and luminescent properties of the transparent germanate glass-ceramics co-doped with Ni2+/Er3+ for near-infrared optical fiber applications was presented. Modification of germanate glasses with 10–20 ZnO (mol.%) was focused to propose the additional heat treatment process controlled at 650 C to obtain transparent glass-ceramics. The formation of 11 nm ZnGa2O4 nanocrystals was confirmed by the X-ray diffraction (XRD) method. It followed the glass network changes analyzed in detail (MIR—Mid Infrared spectroscopy) with an increasing heating time of precursor glass. The broadband 1000–1650 nm luminescence ( exc = 808 nm) was obtained as a result of Ni2+: 3T2(3F) ! 3A2(3F) octahedral Ni2+ ions and Er3+: 4I13/2 ! 4I15/2 radiative transitions and energy transfer from Ni2+ to Er3+ with the efficiency of 19%. Elaborated glass–nanocrystalline material is a very promising candidate for use as a core of broadband luminescence optical fibers

Investigation of the TeO2/GeO2 Ratio on the Spectroscopic Properties of Eu3+-Doped Oxide Glasses for Optical Fiber Application

This study presented an analysis of the TeO2/GeO2 molar ratio in an oxide glass system. A family of melt-quenched glasses with the range of 0–35 mol% of GeO2 has been characterized by using DSC, Raman, MIR, refractive index, PLE, PL spectra, and time-resolved spectral measurements. The increase in the content of germanium oxide caused an increase in the transition temperature but a decrease in the refractive index. The photoluminescence spectra of europium ions were examined under the excitation of 465 nm, corresponding to 7F0 → 5D2 transition. The PSB (phonon sidebands) analysis was carried out to determine the phonon energy of the glass hosts. It was reported that the red (5D0 → 7F2) to orange (5D0 → 7F1) fluorescence intensity ratio for Eu3+ ions decreased from 4.49 (Te0Ge) to 3.33 (Te15Ge) and showed a constant increase from 4.58 (Te20Ge) to 4.88 (Te35Ge). These optical features were explained in structural studies, especially changes in the coordination of [4]Ge to [6]Ge. The most extended lifetime was reported for the Eu3+ doped glass with the highest content of GeO2. This glass was successfully used for the drawing of optical fiber

Antibodies against SARS-CoV-2 S and N proteins in relapsing-remitting multiple sclerosis patients treated with disease-modifying therapies

Clinical rationale for the study. The course of COVID-19 in people with multiple sclerosis (PwMS) has been described, while the serological status after SARS-CoV-2 infection or vaccination, especially in patients treated with disease-modifying therapies (DMT), is still under investigation. This is a significant clinical problem, as certain DMTs may predispose to a severe course of viral infections. Aim of the study. We analyzed the presence of antibodies against spike (S) and nucleocapsid (N) proteins of SARS-CoV-2 in relapsing-remitting PwMS treated with DMT, especially dimethyl fumarate, interferon beta, and glatiramer acetate, in a single multiple sclerosis (MS) centre in north-eastern Poland (the Department of Neurology, Medical University of Bialystok). Material and methods. The presence of antibodies against S and N proteins in PwMS was assessed twice: on visit one (between May and June 2020) (n = 186) and on visit two (between May and June 2021) (n = 88). Samples were taken from 68 individuals on both visits. Demographic and clinical data was collected: duration of MS, Expanded Disability Status Scale Score (EDSS), type of DMT, history of COVID-19 (positive PCR or antigen test in the past), vaccination status, and the type of vaccine. Results. It was shown that on visit one: 3.7% (n = 7) PwMS were positive for IgA against S protein (IgA-S), 3.2% (n = 6) for IgG against S (IgG-S) protein, and none of those examined was positive for IgG against N protein (IgG-N). On visit two, the most common detected antibodies were IgG-S (71.3%; n = 62), then IgA-S (65.1%; n = 55), and the least common was IgG-N (18.2%; n = 16). On visit two: 20.45% of PwMS had a history of a positive SARS-CoV-2 PCR or antigen test during the last year. By the time of visit two, 42.05% (n = 37) of patients who participated in visit two had been full-course vaccinated against COVID-19. It was demonstrated that vaccination against SARS-CoV-2 significantly induces the production of IgG-S and IgA-S (p < 0.0001), while no difference between vaccinated and unvaccinated patients was shown in the detection of IgG-N. There was no correlation between COVID-19 infection and antibodies against proteins S and N in the study group. Moreover, the presented study did not show any relationship between the ability to produce antibodies against the S protein with any of the used DMTs. Conclusions and clinical implications. According to our study, PwMS treated with dimethyl fumarate, interferon beta, or glatiramer acetate can efficiently produce antibodies against SARS-CoV-2 both after infection and after vaccination