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Changcang Huang Deparment of Chemistry, Fuzhou University, Fuzhou, Fujian 350002, People’s Republic of China

Zhenyu You Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, People’s Republic of China (Received 25 September 2003; accepted 7 January 2004)

Yb3+-doped single-crystal Ca3Y2(BO3)4 with dimension ␾20 × 55 mm was grown by the Czochralski method. The structure of it was determined by x-ray diffraction. It belongs to the orthorhombic system, space group Pnma, with the following parameters: a⳱ 7.1690(4), b ⳱ 15.4758(8), c ⳱ 8.5587(6) Å, V ⳱ 949.55(10) Å3, Mr ⳱ 537.51, Z ⳱ 2, Dc ⳱ 3.8 g/cm3, (MoKa) ⳱ 0.71073 Å, F(000) ⳱ 508, ␮ ⳱ 6.927 mm−1, final R ⳱ 0.0670, and wR ⳱ 0.1542 for 2975 independent reflections. The structure of Yb:Ca3Y2(BO3)4 is made up of three set of M-oxygen distorted polyhedrons, and three set of BO3 planar triangles. Ca2+ and Y3+ ions occupy three M sites statistically. Yb3+ ions substitute Y3+ ions to enter these three lattices. The adsorption and emission spectra were measured. It exhibits a broad absorption band ranging from 850 to 1000 nm in the absorption spectrum, which is well matched with the emission wavelength of a laser diode. A broad emission spectrum ranging from 927.95 to 1102.7 nm was observed under the excitation of 895 nm.

I. INTRODUCTION

With the development of laser diodes emitting in the 900–980 nm range, ytterbium-based laser systems for 1 ␮m emission have aroused much interest. Compared with the Nd-based laser systems, they have many advantages in the spectroscopic characteristics.1–7 First, the Yb3+ ion has very simple energy level scheme constituting of only two 2F7/2 and 2F5/2 levels, and the Yb doping level can be very high, leading to a miniaturization of the devices without the problems encountered for the Ndbased laser systems, such as excited-state absorption, luminescence quenching due to the cross-relaxation etc; second, it exhibits smaller quantum defect between adsorption and emission energies: about 6% only whereas 30% for Nd3+ ion, thus the heating ability of the laser rod and its deleterious consequences are reduced. Furthermore, the more intense and much broader Yb3+ absorption lines and longer fluorescence lifetime than Nd3+ ion are well suited for infrared (IR) laser diode pumping. However, the spectroscopic characteristics and laser properties of ytterbium are particularly host-dependant. a)

Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/JMR.2004.0156 J. Mater. Res., Vol. 19, No. 4, Apr 2004

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TheCa3Y2(BO3)4 crystal is a potential laser host material. The 2F7/2 splitting of Yb3+ in this crystal is particularly large (about 850 cm−1) and favorable to a quasithree-level laser operating scheme.7 It has the suitable hardness and good chemical stability and is moisture free. Furthermore, it melts congruently if Yb-doped concentration is less than 20 at.% and can be grown by Czochralski method,8 so we can get h