Past Events

Seminar Announcement: Tatsuya Mori

posted by Stefano Varas   [ updated ]

Announcement
Thursday, 21 March 2019, 15:00
Sala Grande Palazzina B via alla Cascata 56/C

"Boson peak and fracton in glass and single crystal probed by terahertz spectroscopy"

Tatsuya Mori
Division of Materials Science Faculty of Pure and Applied Sciences,
University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8573,
Japan
E-mail: mori@ims.tsukuba.ac.jp

Abstract
In disordered materials, the boson peak (BP) is observed in the terahertz region as a universal feature of atomic vibration [1]. The BP closely relates to the universal temperature behavior of thermal properties of glassy system which is one of the unsolved problems in glass physics. Meanwhile, for polymer glass, the so-called fracton [2] excitation will universally appear in the frequency range above the BP frequency, and it will be originated from the self-similar connectivity of structural units. Interestingly, some particular single crystals such as some thermoelectric materials [3,5] and pure relaxor materials [6], show the universal temperature dependence of thermal properties of glassy system. Those anomalous thermal properties are originated from the off-center rattling phonon modes which correspond to the BP of actual glassy materials [5]. In addition, the fracton in single crystal is observed in the pure relaxors [4,7], by the connection of the dipole-dipole moments having a fractal structure. In the presentation, we show how to detect these universal excitations by terahertz spectroscopy [8] and discuss the difference of behaviors of BP and fracton between actual glass materials and single crystals.

Seminar Announcement: Trevor Benson

posted Mar 5, 2019, 10:40 AM by Stefano Varas   [ updated Mar 5, 2019, 10:40 AM ]

Announcement
Tuesday, 26 February 2019, 10:30
Sala Grande Palazzina B via alla Cascata 56/C

"Assessing the optical properties of chalcogenide glasses at mid-infrared (MIR) wavelengths"

Trevor Benson
George Green Institute for Electromagnetics Research, Faculty of Engineering,
University of Nottingham, University Park, Nottingham, NG7 2RD,
United Kingdom
E-mail: Trevor.Benson@nottingham.ac.uk

Abstract
Abstract Refractive index dispersion is one of the critical parameters that influences the design of optical components. Prism measurements in our laboratory can determine the mid-infrared refractive index of chalcogenide glasses to a standard deviation of precision of less than 0.002. However, shortcomings of this technique are that it requires multiple light sources and intensive sample preparation. The modelling of transmission spectroscopic data [1] is an attractive alternative and was extended by us into the mid-infrared (MIR) region by introducing a two- term Sellmeier equation [2]. This approach determines the refractive index dispersion of chalcogenide glasses to an accuracy of better than 0.4 %. The presentation we will review this method, and discuss its recent extensions to determining very small refractive index contrast and the evaluation of thermo-optic coefficients.

Damiano Massella - La fisica per tutti

posted Jan 30, 2019, 1:21 AM by Stefano Varas   [ updated Jan 30, 2019, 1:23 AM ]

Seminar Announcement: Riccardo Mincigrucci

posted Jan 30, 2019, 12:26 AM by Stefano Varas

Announcement
Tuesday, 29 January 2019, 10:30
Sala Grande Palazzina B via alla Cascata 56/C

"An introduction to FERMI : the Italian free electron laser"

Riccardo Mincigrucci
Elettra Sinctrotrone Trieste SCpA, Strada Statale 14 - km 163, 5, 34149, Basovizza,
Trieste, Italy
E-mail: riccardo.mincigrucci@elettra.eu

Abstract
The continuous development of new light sources in the recent past was mainly driven by free electron lasers (FELs): a technology that extends the laser concept in a region spanning from the EUV to the x-rays. FERMI, located in the Elettra Sincrotrone Trieste campus, distinguish itself in FEL panorama working in a seeded configuration that confer exceptional properties in terms of stability and coherence. Four beamlines are fully operative and two more are in an advanced sate of commissioning. An introduction to the characteristics and capabilities of FERMI will be presented during the talk alongside with some recent experimental results obtained by the beamlines.

Seminar Announcement: Simone Normani

posted Dec 20, 2018, 7:56 AM by Stefano Varas   [ updated Dec 20, 2018, 7:57 AM ]

Announcement
Thursday, 20 December 2018, 15:00
Sala Grande Palazzina B via alla Cascata 56/C

"Er3+-doped Ga-Ge-Sb-S glass PVD: A comparative study of sputtered and PLD thin films"

Simone Normani
University of Pardubice, Department of Graphic Arts and Photophysics,
Pardubický, Czech Republic

Abstract
Despite the renewed interest in rare earth-doped chalcogenide glasses that lies mainly in mid-IR applications, only few comprehensive studies so far have presented the photoluminescence of amorphous chalcogenide films from visible to mid-IR. This study reports the fabrication of luminescent PVD quaternary chalcogenide thin films using RF-sputtering and PLD and their characterization via EDS, SEM, XPS, Raman spectroscopy, AFM and ellipsometry. Several Er3+ emission bands from visible to mid-infrared were clearly observed in the PVD films. The study of 4I13/2 level lifetimes enables development of suitable deposition parameters. The variation in surface roughness is limited, which ensures reasonable optical losses (0.7-0.9 dB/cm). Mid-IR photoluminescence from Er3+- doped micro-waveguide was demonstrated at ~2.76 µm. Finally, the effects of annealing on the chalcogenide films spectroscopy and lifetimes were assessed. The luminescence from the visible to mid-IR generated using erbium doped chalcogenide wave-guiding micro-structures might find easy-to-use applications concerning telecommunication technologies or on-chip optical sensors for which luminescent sources or amplifiers operating at different wavelengths are required.

Seminar Announcement: Mariola Ramirez

posted Dec 5, 2018, 12:23 AM by Stefano Varas   [ updated Dec 5, 2018, 12:23 AM ]

Announcement
Wednesday, 5 December 2018, 15:00
Sala Grande Palazzina B via alla Cascata 56/C

"Interaction between localized surface plasmons and nonlinear solid state gain media"

Mariola Ramirez
Departamento Física de Materiales,
Universidad Autónoma de Madrid

Abstract
Noble metal nanostructures offers a promising perspective for the development of new photonic devices due to their ability to manipulate light in the nano-scale. Their extraordinary capability to couple light with collective oscillations of their conduction-band electrons results in a strong confinement of the electromagnetic energy in the surroundings of the metallic nanostructures. This feature can be used to enhance the interactions between the far-field light and optical emitters placed in close proximity to the metallic nanostructures.
In this context, different arrangements of silver nanoparticles formed on the surfaces of optically active ferroelectric crystals have shown their capability to obtain two types of optical radiation sources with improved performances at the nanoscale: i) Plasmon-assisted Nd3+-based solid state lasers and ii) Plasmon- enhanced Second Harmonic Generation. The mechanisms responsible for the intensification of the radiation–matter interaction processes by localized surface plasmon resonances are analyzed in each case.

Seminar Announcement: Francesco Scotognella

posted Dec 4, 2018, 3:23 AM by Stefano Varas   [ updated Dec 4, 2018, 3:23 AM ]

Announcement
Monday, 3 December 2018, 11:00
Sala Grande Palazzina B via alla Cascata 56/C

"Doped semiconductor nanocrystals for photonic and energy applications"

Francesco Scotognella
Dipartimento di Fisica - Politecnico di Milano,
E-mail: francesco.scotognella@polimi.it

Abstract
Doped semiconductor nanocrystals, as indium tin oxide and copper chalcogenide nanocrystals, are materials with a doping level of about 1021 charges/cm3. Therefore, they exhibit an intense localised surface plasmon resonance in the near infrared. This plasmonic resonance, depending on the number of carriers in the material, can be tuned in several ways, via chemical routes, via electrochemical, electric and optical stimuli.
We show photonic structures that embed doped semiconductor nanocrystals. The photonic structures show a tunable structural colour via photodoping and electrodoping.
Moreover, we discuss the possibility to exploit these nanomaterials, with their strong absorption in the near infrared, for energy applications.

Seminar Announcement: Charlotte Hurel

posted Nov 5, 2018, 8:14 AM by Stefano Varas   [ updated Nov 5, 2018, 8:14 AM ]

Announcement
Monday, 5 November 2018, 11:30
Sala Grande Palazzina C via alla Cascata 56/C

"Capping of marine sediments with valuable industrial by-­products: evaluation of inorganic pollutants immobilization"

Charlotte Hurel
Université Côte d’Azur, Institut de physique de Nice,
Parc Valrose, 06108 Nice Cedex 2, France

Abstract
In-situ capping of polluted sediment is considered as an inexpensive and effective treatment technology to immobilize contaminants in a short time. In this remediation technique sediments are capped by placing a layer of sand, clean sediment or other materials over sediments in order to mitigate risk. During this talk, I will present a bench scale laboratory experiment performed in aquariums to evaluate the effects of low cost industrial by products (bauxaline, steel slag, and their composite) used as capping agents to limit Cd, Zn, As, and Cr mobility from an artificially contaminated marine sediment.

Seminar Announcement: Franck Mady

posted Nov 5, 2018, 8:13 AM by Stefano Varas   [ updated Nov 5, 2018, 8:13 AM ]

Announcement
Monday, 5 November 2018, 10:00
Sala Grande Palazzina C via alla Cascata 56/C

"Role of some rare-earth dopants (Yb, Er, Yb/Ce) in the mechanism of radiation-induced degradation of aluminosilicate-core optical fibers"

Franck Mady
Université Côte d’Azur, CNRS, INФNI, UMR7010,
Parc Valrose, 06108 Nice Cedex 2, France

Abstract
This talk proposes a systematic review of the defects created in silica, in aluminosilicate, and in Yb-, Er- and Yb,Ce-doped silicate or aluminosilicate glasses under ionizing irradiation. The mechanisms of radiation-induced attenuation (RIA) development and annealing, including that of the RIA mitigation by Ce, are also presented. The reduction of rare-earth ions is always observed under irradiation, by electron trapping, accompanied of course by the trapping of holes, preferably at Al-substituted thetrahedral sites. Annealing mechanisms involve the recombination of holes with reduced RE ions, with emission of the charge-transfer relaxation of Yb3+ ions (regardless of co-doping) or that of Er3+ ions. Ce4+ ions are not restored by recombination, but by electron release at moderate temperature (below 500 °C).

Grande finale del progetto “Esploratori della Fotonica”

posted Oct 12, 2018, 2:06 AM by Stefano Varas   [ updated Oct 12, 2018, 2:10 AM ]


Grande finale del progetto “Esploratori della Fotonica” con il concorso vinto dagli studenti dell’ Istituto “Alcide Degasperi” di Borgo Valsugana guidati dalla prof.ssa Monica Ropele con l’esperimento “Il mondo della luce e la luce nel mondo”

Giovedì 11 ottobre gli alunni dei licei Da Vinci e Galilei di Trento, Rosmini di Rovereto e Degasperi di Borgo Valsugana si sono sfidati a suon di esperimenti sulla Luce presso il MuSe.

Il concorso ha concluso un percorso durato un anno svolto nell’ambito del progetto ESFO, coordinato da Andrea Chiappini, ricercatore dell’Istituto di Fotonica e Nanotecnologie IFN-CNR e finanziato dalla Fondazione Caritro.

Il progetto ha visto protagonisti insegnanti e studenti e si è articolato in workshop di formazione per gli insegnanti all’utilizzo di nuove metodologie didattiche e in seminari tematici e visite programmate presso i laboratori di IFN-CNR e FBK, partner di progetto, con l’obiettivo di approfondire concetti teorici e confrontarsi con le tecnologie impiegate nel mondo della ricerca.

Oltre ad aver visto premiato il lavoro svolto con i propri insegnanti, il pomeriggio al MuSe è stato per i ragazzi occasione di scambio di esperienze e di confronto di idee e risultati, da presentare ad altri istituti scolastici, alle famiglie e ad un pubblico generico.

Il gruppo di studenti vincitore è stato premiato con il kit didattico We Lab, offerto dalla ditta DNA Phone, che rappresenta una soluzione innovativa per la misura di parametri chimici e biologici mediante l’uso di dispositivi ottici connessi a piattaforme smart e mobile e con un trofeo offerto dalla Società Italiana di Ottica e Fotonica (SIOF).

http://esfo.fbk.eu/
http://esfo.fbk.eu/attivita/fase-concorsuale/

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