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Guofu Wang Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, China (Received 7 February 2012; accepted 4 June 2012)

Yb31:Sr3Y2(BO3)4 crystals have been grown successfully by Czochralski method. The compound crystallizes in orthorhombic system, space group Pnma, with a 5 7.4062(3) Å, b 5 16.0030(7) Å, c 5 8.7130(4) Å, a 5 b 5 c 5 90°, and Z 5 4. Yb31:Sr3Y2(BO3)4 has three cationic sites and two kinds of boron sites. The crystalline quality of the Yb31:Sr3Y2(BO3)4 single crystal was verified by the width of the x-ray diffraction peak in the x-ray rocking curves measurement. The absorption spectrum, emission spectrum, and fluorescence lifetime of the Yb31:Sr3Y2(BO3)4 crystal were detected at room temperature. The laser performance parameters bmin, Ipsat, and Imin were calculated. I. INTRODUCTION

Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/jmr.2012.210

rotation rate of 15;25 rpm. As a result, Yb31: Sr3Y2(BO3)4 crystal with dimension U12.5  20 mm2, free crack, and inclusion was obtained, as shown in Fig. 1. The x-ray powder diffraction (XRPD) method was used to determine the lattice structure and parameters of the asgrown Yb31:Sr3Y2(BO3)4 crystal. The as-grown crystal of Yb31:Sr3Y2(BO3)4 was ground into powder as a sample to be measured by the XRPD apparatus. The XRPD pattern of Yb31:Sr3Y2(BO3)4 crystal is shown in Fig. 2, which was performed using a D–max-rA type diffractometer with a powder, using Cu Ka radiation (k 5 1.54056 Å) by using a graphite monochromator at room temperature. The x-ray diffraction (XRD) data for structure refinement were collected in the step scan mode with steps of 0.020 (2h). The obtained d values, Miller index, and the corresponding intensities of the peaks are shown in Fig. 2. The crystallinity of the Yb31:Sr3Y2(BO3)4 samples was investigated by x-ray rocking curve (XRC) analysis for the (020) peak using a multipurpose advanced thin film x-ray system with an extra high resolution Rigaku diffractometer (Tokyo, Japan), which was evaluated based on the full width at half maximum (FWHM) of the peak. A sample of Yb31:Sr3Y2(BO3)4 crystal with dimensions 2.1  2  3 mm3 was cut from as-grown crystal for measurement of absorption and emission spectrum. The absorption spectrum was measured using a Perkin-Elmer UV–VIS–NIR (Lambda 35, Norwalk, CT) spectrophotometer at room temperature, which was measured in the range from 800 to 1100 nm. Photoluminescence spectrum was measured at room temperature using Edinburgh Analytical Instruments FLS 920 LifeSpec Ps spectrophotometer (Edinburgh, UK), which contained a Hamamatsu/R5509 photodetector (Hamamatsu, Japan).

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Ó Materials Research Society 2012

With the development of high-power InGaAs laser diode in the early 1990s, Yb31-doped laser materials as promising materials for diode-pumped solid-state highpower lasers with wave lengths between 0.9 and 1.1 lm have been gained much attention.1–3