Pulsed laser deposition of rare-earth doped glasses: a step toward lightwave circuits
10 págs.; 7 figs.; Optical Components and Materials XIII ; Pulsed Laser Deposition (PLD) is used to produce Er-doped lead-niobium germanate (PbO¿Nb2O5¿GeO2) and fluorotellurite (TeO2¿ZnO¿ZnF2) thin film glasses. Films having high refractive index, low absorption and large transmission are obtained in a narrow processing window that depends on the actual PLD configuration (O2 pressure: a few Pa, Laser energy density: 2-3 J cm-2 for the results presented in this work). However, Er-doped thin film glasses synthetized at room temperature using these experimental parameters show poor photoluminescence (PL) performance due to non-radiative decay channels, such as a large OH- concentration. Thermal annealing allows improving PL intensity and lifetime (TPL), the latter becoming close to that of the parent Er-doped bulk glass. In addition, the use of alternate PLD from host glass and rare-earth targets allows the synthesis of nanostructured thin film glasses with a controlled rare-earth concentration and in-depth distribution, as it is illustrated for Er-doped PbO-Nb2O5-GeO2 film glasses. In this case, PL intensity at 1.53 microns increases with the spacing between Er-doped layers to reach a maximum for a separation between Er-doped layers close to 5 nm, while TPL is close to the bulk value independently of the spacing. Finally, the comparison of these results with those obtained for films grown by standard PLD from Er-doped glass targets suggests that nanostructuration allows reducing rare-earth clustering and concentration quenching effects. © 2016 SPIE ; We acknowledge J. García-Lopez from the Centro Nacional de Aceleradores (CNA, Spain) and B. Mate from the Instituto de Estructura de la Materia (IEM, CSIC, Spain) for Ion beam and FTIR analysis, respectively. We thank R. Serna from the Instituto de Optica and past PhD students at the Institute, D. Munoz-Martin and O. Sanz for their contribution to different parts of the results presented. This work was supported by the Spanish Government MINECO under Projects No. TEC2012-38901-C02-01 and MAT2013-48246-C2-2-P and the Basque Country Government IT943- 16. R. Morea acknowledges a FPI grant from the Spanish Government. ; Peer Reviewed
