Spectroscopic properties and up
Transkrypt
Spectroscopic properties and up
ESTE5 – POSTERS P17 Spectroscopic properties and up-conversion in KYb(WO4)2: Ho3+ P.J. Dere na , A.A. Demidovichb, J-C. Krupa c, W. Streka a Instytut Niskich Temperatur i Badañ Strukturalnych PAN, ul. Ok olna 2, Skr. Poczt. 1410, 50-950 Wroclaw 2, Poland, E-mail: [email protected] b Laser Spectroscopy Laboratory, Institute of Molecular and Atomic Physics, F. Skaryna ave.70, Minsk, 220072,Belarus c Institue de Physique Nucleare, CNRS, IN2P3, 91406 Orsay Cedex, France Double tungstate crystal is a very interesting host for Rare Earth ions. Firstly Rare Earth ions' absorption bands are broader than in YAG for example. This is very beneficial when a laser crystal is excited by a laser diode, which emission wavelength changes with temperature. Secondly the double tungstates being monoclinic offers another advantageous feature – they are non- linear. These properties allowed obtaining in the double tungstates doped with Nd3+ self-stimulated Raman scattering [1]. Holmium is also widely investigated nowadays; it is an interesting ion for anti-Stokes emission including photon avalanche upconversion [2]. KGd(WO 4 )2 : Ho3+ double tungstate was successfully used to obtain stimulated emission in the IR [3]. The reader will find a preliminary report on KYb(WO 4 )2 : Ho3+ in [4]. S I To enhance emission’s quantum efficiency Yb is added into crystals as a sensitiser, the strong Yb 3+ absorption band match very well the emission of IR laser diodes. In this work we present the results of investigations of KYb(WO 4 )2 : Ho3+ (0,6 %). S I The single crystal was excited either by pulse IR excitation at 1064 nm and cw excitation at F I F I 989 nm. Both excitations produces strong upconversion emission of Ho 3+ ions in the red 500 550 600 650 700 750 800 and green region, a strong IR emission was Wavelength [nm] Up conversion emission spectrum of observed as well. The peaks are observed at KYb(WO4 )2 : Ho 3+ , λexc= 1064 nm, T = 300 K. 476.8 nm, 545.6 nm, 658 nm and at 754 nm (the 5 F3 → 5 I8 , 5 S2 →5 I8 , 5F5 → 5 I8 and the 5 5 S2 → I7 transition respectively). At 2058 nm the 5 I7 → 5 I8 transition is observed. Decay time of the green anti-Stokes emission is multi exponential; three components were found 154 µs, 320 µs and 6.4 ms. A characteristic for energy transfer up-conversion rise time of 70 µs was observed as well. The possible mechanisms of observed anti-Stokes emission are discussed. 5 5 Intensity [a.u.] 2 8 5 5 2 5 5 3 5 8 7 5 5 8 References: [1] A.S. Grabtchicov, A.N. Kuzmin, V.A. Lisinetskii, V.A. Orlovich and G.I. Ryabtsev, A.A. Demidovivh, Apll. Phys. Lett. 75, No 24 (1999) 3742. [2] M. Malinowski, R. Piramidowicz, Z. Frukacz, G. Chadeyron, R. Mahiou, M.F. Joubert, Optical Materials 12 (1999) 409. [3] AA. Kaminskii, AA. Pavluk, PV. Klevcov, FI. Balashkov, WA, Berenberg, SE. Sarkisov, WA. Fiedorov, MW. Pietrov, WW. Lubchenko, Neorganicheskie Mat. 13 No 3, (1977)582. [4] L. Macalik, P.J. Dereñ, J. Hanuza, W. Strêk, A.A. Demidovich, A.N. Kuzmin, J. Mol. Struct. 450 (1998) 179.