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GaS 3/2 Cl)units surround the lanthanide ions in GGS-CsCl glasses. IV. Optical Properties of Lanthanide(III) Ions in Non-Oxide GlassesNon-oxide glasses are hosts of prime interest for rare-earth spectroscopy. They show low phonon energies, which induce high quantum efficiencies of rareearth emissions. Thus, a number of transitions, which cannot be detected in silica-based rare-earthdoped glasses, are observed in non-oxide glasses.

We describe the spectroscopic properties of the trivalent lanthanide ions Ce 3 , Pr 3 , Nd 3 , Sm 3 , Eu 3 , Gd 3 , Tb 3 , Dy 3 , Ho 3 , Er 3 , Tm 3 and Yb 3 in the¯uorophosphate glasses 75NaPO 3 ±24CaF 2 ±1LnF 3 and 75NaPO 3 ±20CaF 2 ± 5LnF 3 (where Ln lanthanide ion). Absorption and luminescence spectra are discussed. The dipole strengths of the transitions in the absorption spectrum are parametrized in terms of three X k (k 2, 4 and 6) Judd±Ofelt intensity parameters. These phenomenological parameters are used to predict the luminescence properties of the lanthanide ions in the¯uorophosphate glasses. Attention is paid to the trend of the intensity parameters over the lanthanide series. á 1998 Elsevier Science B.V. All rights reserved.

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International audienceHigh second-order susceptibilities are created by thermal poling in bulk germanium disulfide based chalcogenide glasses. Experimental conditions of the poling treatment (temperature, voltage, time) were optimized for each glass composition. The second-order nonlinear signals were recorded by using the Maker fringes experiment and a second-order coefficient χ(2) up to 8 pm V-1 was measured in the Ge25Sb10S65 glass. This value is obtained using a simulation based on accurate knowledge of the thickness of the nonlinear layer. Two mechanisms are proposed to explain the creation of a nonlinear layer under the anode: the formation and the migration of charged defects towards the anode may mainly occur in Ge20Ga5Sb10S65 and Ge25Ga5S70 glasses, whereas the migration of Na+ ions towards the cathode may be responsible for the accumulation of negative charges under the anode in Ge33S67 and Ge25Sb10S65 glasses. Different electronic conductivity behaviors seem to be at the origin of the phenomenon. In parallel, the potential effect of the poling treatment on the structural and electronic properties is studied using Raman spectroscopy and secondary ion mass spectroscopy measurements

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