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
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989 nm. Both excitations produces strong upconversion emission of Ho 3+ ions in the red
500
550
600
650
700
750
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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
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Intensity [a.u.]
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8
5
5
2
5
5
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5
8
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5
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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.