Red photonic glasses and confined structures

We present some recent results obtained by our team in rare earth doped photonic glasses and confined structures, in order to give some highlights regarding the state of art in glass photonics. To evidence the unique properties of transparent glass ceramics we compare spectroscopic and structural properties between the parent glass and the glass ceramics. Starting from planar waveguides we move to spherical microresonators, a very interesting class of photonic confined structures. We also conclude the short review with some remarks about the perspective for glass photonics

Low Temperature Deposition of SiNx Thin Films by the LPCVD Method

Thin silicon rich nitride (SiNx) films were deposited using the LPCVD (Low Pressure Chemical Vapor Deposition) method. Silane diluted in argon and ammonia were used as the reactant gasses, and the low temperature deposition at 570 °C was used. The films were deposited on silicon (111) substrates. Films with the different values of the nitrogen content were deposited by varying the ratio of the flows of ammonia and silane in the horizontal tube reactor. The films were characterized in terms on the surface quality (by scanning electron microscopy), in terms of the nitrogen content x by time of flight elastic recoil detection analysis and by Raman and FTIR spectroscopy. The thickness and dielectric constant were measured by ellipsometry. The films were found to have a very smooth, homogeneous surface with nitrogen content that vary from x = 0 to x = 1 in dependence on the deposition parameters. The intensity of the Si–N stretching peak has shown strong correlation with the film thickness measured by ellipsometry. The films showed a smooth surface layer and the value of dielectric constant easily controllable by the ratio of the flow of the gases in the reactor. (doi: 10.5562/cca1970

Coherent emission from fully Er 3+ doped monolithic 1-D dielectric microcavity fabricated by rf-sputtering

All Er3+ doped dielectric 1-D microcavity was fabricated by rf sputtering technique. The microcavity was constituted by half wave Er3+ doped SiO2 active layer inserted between two Bragg reflectors consists of ten pairs of SiO2/TiO2 layers also doped with Er3+ ions. The scanning electron microscopy was used to check the morphology of the structure. Transmission measurements confirm the third and first order cavity resonance at 530 nm and 1560 nm, respectively. The photoluminescence measurements were obtained by optically exciting at the third order cavity resonance using 514.5 nm Ar+ laser with an excitation angle of 30°. The Full Width at Half Maximum of the emission peak at 1560 nm decrease with the pump power until the spectral resolution of the detection system of ∼1.0 nm. Moreover, the emission intensity presents a non-linear behavior with the pump power and a threshold at about 24 mW was observed with saturation of the signal at above 185 mW of pump power

Photonic band edge assisted spontaneous emission enhancement from all Er3+ 1-D photonic band gap structure

International audienceAll Er3+ doped dielectric 1-D Photonic Band Gap Structure was fabricated by rf-sputtering technique. The structure was constituted by of twenty pairs of SiO2/TiO2 alternated layers doped with Er3+ ions. The scanning electron microscopy was used to check the morphology of the structure. Transmission measurements put in evidence the stop band in the range 1500 nm–1950 nm. The photoluminescence measurements were obtained by optically exciting the sample and detecting the emitted light in the 1.5 μm region at different detection angles. Luminescence spectra and luminescence decay curves put in evidence that the presence of the stop band modify the emission features of the Er3+ ions

Fabrication by rf-sputtering and assessment of dielectric Er3+ doped monolithic 1-D microcavity for coherent emission at 1.5 um

International audienceAll Er3+ doped dielectric 1-D microcavity are fabricated by RF sputtering technique. The microcavity is composed of half wave Er3+ doped SiO2 active layer inserted, between two Bragg reflectors consisting of seven pairs of SiO2/TiO2 layers also doped with Er3+ ions. The morphology of the structure is inspected with scanning electron microscopy. Transmission measurements show the third and first order cavity resonance at 530 nm and 1535 nm, respectively. The photoluminescence measurements were obtained by optically exciting at the third order cavity resonance using 514.5 nm Ar+ laser with an excitation angle of 30°. The Full Width at Half Maximum of the emission peak at 1535 nm decrease with the pump power until the spectral resolution of the detection system of 2.3 nm. Moreover, the emission intensity presents a non-linear behavior with the pump power and a threshold at about 4 μW

Low-Threshold Coherent Emission at 1.5 µm from Fully Er3+ Doped Monolithic 1D Dielectric Microcavity Fabricated Using Radio Frequency Sputtering

none14siLow threshold coherent emission at 1.5 μm is achieved using Er3+-doped dielectric 1D microcavities fabricated with a Radio Frequency-sputtering technique. The microcavities are composed of a half-wavelength Er3+-doped SiO2 active layer inserted between two Bragg reflectors consisting of ten, five, and seven pairs of SiO2/TiO2 layers, also doped with Er3+ ions. The morphology of the structure is inspected using scanning electron microscopy. Transmission measurements show the third and first order cavity resonance at 530 nm and 1.5 μm, respectively. The photoluminescence measurements are obtained using the optical excitation at the third order cavity resonance using a 514.5 nm Ar+ laser or Xe excitation lamp at 514.5 nm, with an excitation angle of 30º. The full width at half maximum of the emission peak at 1535 nm decreased with the pump power until the spectral resolution of the detection system was 2.7 nm. Moreover, the emission intensity presents a non-linear behavior with the pump power and a threshold at about 4 μW.noneCesare Meroni, Francesco Scotognella, Yann Boucher, Anna Lukowiak, Davor Ristic, Giorgio Speranza, Stefano Varas, Lidia Zur, Mile Ivanda, Stefano Taccheo, Roberta Ramponi, Giancarlo C. Righini, Maurizio Ferrari, Alessandro ChiaseraMeroni, Cesare; Scotognella, Francesco; Boucher, Yann; Lukowiak, Anna; Ristic, Davor; Speranza, Giorgio; Varas, Stefano; Zur, Lidia; Ivanda, Mile; Taccheo, Stefano; Ramponi, Roberta; Righini, Giancarlo C.; Ferrari, Maurizio; Chiasera, Alessandr

Towards a full and realistic simulation framework for the Extreme Energy Events experiment

The network of MRPC (Multi-gap Resistive Plate Chambers) telescopes of the Extreme Energy Events experiment (EEE) was designed to study very high energy cosmic rays through detection of secondary cosmic muons in the hadronic shower. To better understand and predict the behavior of such events, a GEANT4-based simulation framework that well reproduces the response of individual telescopes was built. Simulations are crucial to better understand the detectors performance in current setup and how these are affected by the specific installations. This is the first step towards a full simulation framework that includes a realistic generation, now limited to muons, of secondary particles and propagation through the atmosphere of the shower produced by primary rays. The current framework can be used to characterize and optimize the array of EEE telescopes, simulating not only the single detectors but also telescope's clusters, providing insight in extreme energy and rare events. In this contribution, the EEE simulation framework and future plans will be presented

Looking for long-range correlations among the EEE telescopes

none60siThe search for long-range correlations among air showers is one of the main goal of the Extreme Energy Events (EEE) Project. The existence of such events has only been supposed theoretically through several physical mechanisms, the most convincing being the so-called GZ effect, based on the photodisintegration of a heavy primary nucleus in the solar field. Even with a large detector coverage, current rate expectations are of few events per year. To measure time correlations among distant air showers, sparse arrays of detection stations spread over large areas are needed. A very limited number of experimental setups can perform this measurement and few experimental results have been reported over the past years. Started in 2004 the EEE project is a network of about 60 cosmic muons tracking telescopes made by 3 wide area Multigap Resistive Plate Chambers (MRPCs), sensitive to the direction of incident charged cosmic particles. The telescopes are distributed over the whole Italian territory, thus making the EEE array an ideal tool for the detection of long-range time correlations among extensive air showers. In this paper we will describe the analysis strategies adopted to search for such rare correlation events, together with the results obtained analysing the full statistics collected by the EEE telescopes.restrictedLa Rocca, P.; Abbrescia, Marcello; Avanzini, Carlo; Baldini, Luca; Baldini Ferroli, Rinaldo; Batignani, Giovanni; Battaglieri, Marco; Boi, Stefano; Bossini, Edoardo; Carnesecchi, Francesca; Cicalo, Corrado; Cifarelli, Luisa; Coccetti, Fabrizio; Coccia, Eugenio; Corvaglia, Alessandro; De Gruttola, Daniele; De Pasquale, Salvatore; Fabbri, Franco L.; Galante, Lorenzo; Garbini, Marco; Gemme, Gianluca; Gnesi, Ivan; Grazzi, Stefano; Hatzifotiadou, Despina; Liu, Zheng; Mandaglio, Giuseppe; Maron, Gaetano; Mazziotta, Mario Nicola; Mulliri, Alice; Nania, Rosario; Noferini, Francesco; Nozzoli, Francesco; Palmonari, Federico; Panareo, Marco; Panetta, Maria Paola; Paoletti, Riccardo; Pellegrino, Carmelo; Pinazza, Ombretta; Pinto, Chiara; Pisano, Silvia; Riggi, Francesco; Righini, Giancarlo Cesare; Ripoli, Cristina; Rizzi, Matteo; Sartorelli, Gabriella; Scapparone, Eugenio; Schioppa, Marco; Scribano, Angelo; Selvi, Marco; Serri, Gabriella; Squarcia, Sandro; Taiuti, Mauro; Terreni, Giuseppe; Trifirò, Antonio; Trimarchi, Marina; Vistoli, Cristina; Votano, Lucia; Williams, Crispin; Zichichi, Antonino; Zuyeuski, RomanLa Rocca, P.; Abbrescia, Marcello; Avanzini, Carlo; Baldini, Luca; Baldini Ferroli, Rinaldo; Batignani, Giovanni; Battaglieri, Marco; Boi, Stefano; Bossini, Edoardo; Carnesecchi, Francesca; Cicalo, Corrado; Cifarelli, Luisa; Coccetti, Fabrizio; Coccia, Eugenio; Corvaglia, Alessandro; De Gruttola, Daniele; De Pasquale, Salvatore; Fabbri, Franco L.; Galante, Lorenzo; Garbini, Marco; Gemme, Gianluca; Gnesi, Ivan; Grazzi, Stefano; Hatzifotiadou, Despina; Liu, Zheng; Mandaglio, Giuseppe; Maron, Gaetano; Mazziotta, Mario Nicola; Mulliri, Alice; Nania, Rosario; Noferini, Francesco; Nozzoli, Francesco; Palmonari, Federico; Panareo, Marco; Panetta, Maria Paola; Paoletti, Riccardo; Pellegrino, Carmelo; Pinazza, Ombretta; Pinto, Chiara; Pisano, Silvia; Riggi, Francesco; Righini, Giancarlo Cesare; Ripoli, Cristina; Rizzi, Matteo; Sartorelli, Gabriella; Scapparone, Eugenio; Schioppa, Marco; Scribano, Angelo; Selvi, Marco; Serri, Gabriella; Squarcia, Sandro; Taiuti, Mauro; Terreni, Giuseppe; Trifirò, Antonio; Trimarchi, Marina; Vistoli, Cristina; Votano, Lucia; Williams, Crispin; Zichichi, Antonino; Zuyeuski, Roma

Prosafe: a european endeavor to improve quality of critical care medicine in seven countries

BACKGROUND: long-lasting shared research databases are an important source of epidemiological information and can promote comparison between different healthcare services. Here we present ProsaFe, an advanced international research network in intensive care medicine, with the focus on assessing and improving the quality of care. the project involved 343 icUs in seven countries. all patients admitted to the icU were eligible for data collection. MetHoDs: the ProsaFe network collected data using the same electronic case report form translated into the corresponding languages. a complex, multidimensional validation system was implemented to ensure maximum data quality. individual and aggregate reports by country, region, and icU type were prepared annually. a web-based data-sharing system allowed participants to autonomously perform different analyses on both own data and the entire database. RESULTS: The final analysis was restricted to 262 general ICUs and 432,223 adult patients, mostly admitted to Italian units, where a research network had been active since 1991. organization of critical care medicine in the seven countries was relatively similar, in terms of staffing, case mix and procedures, suggesting a common understanding of the role of critical care medicine. conversely, icU equipment differed, and patient outcomes showed wide variations among countries. coNclUsioNs: ProsaFe is a permanent, stable, open access, multilingual database for clinical benchmarking, icU self-evaluation and research within and across countries, which offers a unique opportunity to improve the quality of critical care. its entry into routine clinical practice on a voluntary basis is testimony to the success and viability of the endeavor

Second asymptomatic carotid surgery trial (ACST-2) : a randomised comparison of carotid artery stenting versus carotid endarterectomy

Background: Among asymptomatic patients with severe carotid artery stenosis but no recent stroke or transient cerebral ischaemia, either carotid artery stenting (CAS) or carotid endarterectomy (CEA) can restore patency and reduce long-term stroke risks. However, from recent national registry data, each option causes about 1% procedural risk of disabling stroke or death. Comparison of their long-term protective effects requires large-scale randomised evidence. Methods: ACST-2 is an international multicentre randomised trial of CAS versus CEA among asymptomatic patients with severe stenosis thought to require intervention, interpreted with all other relevant trials. Patients were eligible if they had severe unilateral or bilateral carotid artery stenosis and both doctor and patient agreed that a carotid procedure should be undertaken, but they were substantially uncertain which one to choose. Patients were randomly allocated to CAS or CEA and followed up at 1 month and then annually, for a mean 5 years. Procedural events were those within 30 days of the intervention. Intention-to-treat analyses are provided. Analyses including procedural hazards use tabular methods. Analyses and meta-analyses of non-procedural strokes use Kaplan-Meier and log-rank methods. The trial is registered with the ISRCTN registry, ISRCTN21144362. Findings: Between Jan 15, 2008, and Dec 31, 2020, 3625 patients in 130 centres were randomly allocated, 1811 to CAS and 1814 to CEA, with good compliance, good medical therapy and a mean 5 years of follow-up. Overall, 1% had disabling stroke or death procedurally (15 allocated to CAS and 18 to CEA) and 2% had non-disabling procedural stroke (48 allocated to CAS and 29 to CEA). Kaplan-Meier estimates of 5-year non-procedural stroke were 2·5% in each group for fatal or disabling stroke, and 5·3% with CAS versus 4·5% with CEA for any stroke (rate ratio [RR] 1·16, 95% CI 0·86-1·57; p=0·33). Combining RRs for any non-procedural stroke in all CAS versus CEA trials, the RR was similar in symptomatic and asymptomatic patients (overall RR 1·11, 95% CI 0·91-1·32; p=0·21). Interpretation: Serious complications are similarly uncommon after competent CAS and CEA, and the long-term effects of these two carotid artery procedures on fatal or disabling stroke are comparable