Er3+/Yb3+ - activated silica–hafnia planar waveguides for photonics fabricated by rf-sputtering
The spectrum of Figure 1 shows the emission band located at 1500 nm due to the emission of erbium ions, and the emission band with a peak at 978 nm and a smaller peak at 1010 nm, typical of the ytterbium ion emissions in glasses. This pattern is an indication of the presence of the back energy transfer from Er3+ to Yb3+ ions. In fact, using the 514.5 nm laser line we excite directly only the Er3+ ions but an emission relative to the 2F5/2→2F7/2 transition of Yb3+ is observed. Nevertheless, the PL excitation spectra reported in figure 2 indicates that an effective energy transfer from Ytterbium to Erbium ions is present. In fact, as reported in Figure 2, the spectral shape of the excitation spectrum corresponds of the sample co-activated with Ytterbium ions to the typical Ytterbium absorption.
A. Chiasera, C. Armellini, S.N.B. Bhaktha, A. Chiappini, Y. Jestin, M. Ferrari, E. Moser, A. Coppa, V. Foglietti, P.T. Huy, K. Tran Ngoc, G. Nunzi Conti, S. Pelli, G.C. Righini, G. Speranza, "Er3+/Yb3+-activated silica-hafnia planar waveguides for photonics fabricated by rf-sputtering", Journal of Non-Crystalline Solids 355 (2009), pp. 1176–1179.
Infrared-to-visible CW frequency upconversion in erbium activated silica–hafnia waveguides prepared by sol–gel route
The value of the slope n, obtained by fitting the measured upconversion intensity as a function of the excitation power, indicates that two photons are involved in the infrared-to-green and three photons are involved in the infrared-to-blue upconversion processes.
R.R. Gonçalves, G. Carturan, L. Zampedri, M. Ferrari, A. Chiasera, M. Montagna, G.C. Righini, S. Pelli, S.J.L. Ribeiro, Y. Messaddeq, “Infrared-to-visible CW frequency upconversion in erbium activated silica–hafnia waveguides prepared by sol–gel route”, J. Non-Crystalline Solids 322 (2003), 306.
Down-converter based on rare earth doped fluoride glass to improve Si-based solar cell efficiency
Efficient down-conversion bulks Pr3+-Yb3+ co-doped ZLAG glasses have been developed. Emission of the ytterbium at 980 nm was observed after excitation of the praseodymium at 476 nm. We evaluated the energy transfer efficiency for the 3P0 state of the praseodymium to the ytterbium ions for the first step of the quantum cutting process. We observed an increase of the energy transfer efficiency with the concentration of ytterbium ions. The sample with 0.5 mol% of praseodymium and 10 mol% of ytterbium presents an energy transfer efficiency of 92%, similar to the best results obtained in fluoride crystals with the same doping.
G. Alombert Goget, D. Ristic, A. Chiasera, S. Varas, M. Ferrari, G. C. Righini, B. Dieudonné, B. Boulard, "Down-converter based on rare earth doped fluoride glass to improve Si-based solar cell efficiency", Proc. SPIE 8069, Integrated Photonics: Materials, Devices, and Applications, 80690N (May 31, 2011), doi:10.1117/12.886789.
B. Dieudonné, B. Boulard, G. Alombert-Goget, A. Chiasera, Y. Gao, S. Kodjikian, M. Ferrari, "Up- and down-conversion in Yb3+-Pr3+ co-doped fluoride glasses and glass ceramics", Journal of Non-Crystalline Solids 377 (2013) pp. 105-109.
G. Alombert-Goget, D. Ristic, A. Chiasera, S. Varas, M. Ferrari, G. C. Righini, B. Dieudonne, B. Boulard, "Rare-earth doped materials enhance silicon solar cell efficiency", 22 June 2011, SPIE Newsroom, doi: 10.1117/2.1201105.003701.
Silica-Hafnia coated spherical microresonators
A. Chiasera, Y. Dumeige, P. Féron, M. Ferrari, Y. Jestin, G. Nunzi Conti, S. Pelli, S. Soria, G.C. Righini, “Spherical whispering-gallery-mode microresonators”, Laser & Photonics Reviews 4 (2010), pp. 457-482, doi: 10.1002/lpor.200910016.