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Photonic properties and applications of glass micro‐ and nanospheres
Author(s) -
Righini Giancarlo C.,
Cosi Franco,
Conti Gualtiero Nunzi,
Pelli Stefano,
Soria Silvia,
Moser Enrico,
Jestin Yoann,
Ferrari Maurizio,
Féron Patrice,
Chiasera Alessandro,
Chiappini Andrea,
Armellini Cristina
Publication year - 2009
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.200881335
Subject(s) - materials science , photoluminescence , spheres , lasing threshold , sol gel , nanotechnology , integrating sphere , doping , chemical engineering , fabrication , whispering gallery wave , composite material , optics , optoelectronics , wavelength , medicine , physics , alternative medicine , engineering , pathology , resonator , astronomy
Abstract Fabrication, morphological and spectroscopic assessment of micro‐ and nano‐spheres are reported. Spheres with size ranging from few hundreds of nm to few hundreds of μm have been prepared by different methods, i.e. sol–gel, melting and core‐shell techniques. Pure and rare‐earth‐doped spheres find their major applications as microsensors and microlasers, respectively. We refer here to Erbium‐activated systems only: (i) coated micro spheres where the silica core, obtained by telecom fiber melting, is coated with an Er 3+ –70SiO 2 –30HfO 2 film; (ii) Er 3+ ‐activated microspheres obtained from silicate‐modified glasses and phosphate glasses using a plasma torch; (iii) sol–gel Er 3+ ‐doped silica micro‐ and nano‐spheres. The whispering gallery mode spectra were analysed as a function of sphere diameter, thickness of coating (if any) and Erbium content. Photoluminescence spectra of different systems gave interesting indications on the potential of some activated microspheres for lasing applications. For instance, sol–gel Er 3+ ‐activated core‐shell‐like structures exhibited a lifetime of 12.8 ms, leading to a quantum efficiency (QE) of 71%. Even higher QE (∼76%) was estimated in sol–gel Er 3+ ‐silica spheres. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)