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Lukowiak A.,CNR Institute for Photonics and Nanotechnologies | Lukowiak A.,Institute of Low Temperature And Structure Research | Wiglusz R.J.,Institute of Low Temperature And Structure Research | Chiappini A.,CNR Institute for Photonics and Nanotechnologies | And 6 more authors.
Journal of Non-Crystalline Solids | Year: 2014

Nanoparticles of lithium lanthanum tetraphosphates doped with different concentration of Eu3 + ions were synthesized. The selected tetraphosphate was used to fabricate a transparent composite where nanocrystals were immobilized in a sol-gel-derived silica-hafnia amorphous film. The structural and spectroscopic properties of the systems were investigated by XRD analysis, Raman spectroscopy, and photoluminescence measurements. For all the samples with the Eu3 + ions concentration from 1 to 100 mol% the monoclinic structure with a space group C12/c1 was determined. The mean diameter of nanocrystals determined by Scherrer equation was in the range of 40-55 nm. The luminescence of 10%Eu3 +:LiLa(PO3)4 in silica-hafnia matrix indicated the immobilization of Eu3 + ions into a distorted environment. The dependence of both luminescence intensity and lifetime on the Eu3 + concentration demonstrated effective reduction of concentration quenching in the tetraphosphate nanopowders. © 2013 Elsevier B.V.


Berneschi S.,Centro Of Studi E Ricerche Enrico Fermi | Berneschi S.,CNR Institute of Neuroscience | Chiappini A.,CNR Institute for Photonics and Nanotechnologies | Ferrari M.,CNR Institute for Photonics and Nanotechnologies | And 2 more authors.
Physica Status Solidi (C) Current Topics in Solid State Physics | Year: 2011

Aim of this paper is to present a short review of the main results obtained in our laboratories on Er3+-doped SiO2: HfO2 glass ceramic waveguides fabricated by sol-gel route and dip-coating technique, employing either top-down or bottom-up approach. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Berneschi S.,Centro Of Studi E Ricerche Enrico Fermi | Berneschi S.,CNR Institute of Neuroscience | Brenci M.,CNR Institute of Neuroscience | Nunzi Conti G.,CNR Institute of Neuroscience | And 11 more authors.
Optical Engineering | Year: 2011

Slab optical waveguides were fabricated in tung-sten-tellurite glass doped with Er3 ions by means of nitrogen ion implantation at 1.5 MeV. A wide range of ion doses (from 51012 to 8.1016 ionscm 2) was used. Optical characterization, performed by dark-line spectroscopy, revealed that the waveguides were of optical barrier type: the implanted layer exhibited a decrease of the refractive index with respect to the virgin bulk glass, while the region comprised between the sample surface and the end of the ion track acted as an optical guiding structure. It was also demonstrated that a post-implantation annealing process, performed at various temperatures on the samples implanted at higher doses, contributes to the reduction of the barrier region. © 2011 Society of Photo-Optical Instrumentation Engineers (SPIE).


Ristic D.,Ruder Boskovic Institute | Guddala S.,Indian Institute of Technology Kanpur | Chiappini A.,CNR Institute for Photonics and Nanotechnologies | Alombert Goget G.,University Claude Bernard Lyon 1 | And 7 more authors.
Journal of Applied Physics | Year: 2015

The thermo-optic coefficient of tin-oxide thin films on silicon substrates was measured using fixed wavelength ellipsometry. The applicability of ellipsometry for these measurements is discussed with special considerations to the problem of measurement of the thermo-optic coefficient of materials with very low values of the thermo-optic coefficient (<2 × 10-5). The effect of thermal annealing on the thermo-optic coefficient and on the film-substrate boundary properties of the tin oxide film is also discussed. © 2015 AIP Publishing LLC.


Chiasera A.,CNR Institute for Photonics and Nanotechnologies | Scotognella F.,CNR Institute for Photonics and Nanotechnologies | Scotognella F.,Italian Institute of Technology | Valligatla S.,CNR Institute for Photonics and Nanotechnologies | And 16 more authors.
Optical Materials | Year: 2016

We have developed a reliable RF sputtering techniques allowing to fabricate glass-based one dimensional microcavities, with high quality factor. This property is strongly related to the modification of the density of states due to the confinement of the gain medium in a photonic band gap structure. In this short review we present some of the more recent results obtained by our team exploiting these 1D microcavities. In particular we present: (1) Er3+ luminescence enhancement of the 4I13/2 → 4I15/2 transition; (2) broad band filters based on disordered 1-D photonic structures; (3) threshold defect-mode lasing action in a hybrid structure. © 2016.

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