Spectral and luminescent properties of Yb 3þ ions in YCa 4 OðBO 3 Þ 3 crystal HuaidongJiang a,b, * ,JiyangWang a ,HuaijinZhang a ,XiaoboHu a ,PhilBurns c , James A. Piper c a National Laboratory of Crystal Materials, Shandong University, Jinan 250100, People’s Republic of China b National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210008, People’s Republic of China c Department of Physics, Center for Lasers and Applications, Macquarie University, NSW 2109, Australia Received 23 April 2002; in final form 14 June 2002 Abstract Yb:YCa 4 OðBO 3 Þ 3 crystal with large sizes and good optical quality has been grown by the Czochralski method. The spectroscopic properties have been investigated and compared with those of other Yb-doped laser crystals. The ab- sorption and emission cross-sections, the minimum fraction, the pump saturation intensity of Yb 3þ have been calcu- lated. The ground-state energy-level splitting is up to 1012 cm 1 and the measured emission lifetime of Yb 3þ is2.65ms. The calculated luminescence parameters show that Yb:YCa 4 OðBO 3 Þ 3 crystal satisfies the fundamental spectral con- dition for laser emission. Ó 2002 Elsevier Science B.V. All rights reserved. 1. Introduction Nowadays, much attention has been focused on diode-pumped lasers because diode lasers offer many desirable properties such as compactness and high efficiency for laser applications [1,2]. The ytterbium ion is ideally suited for diode pumping since it has low absorption of the excitation state and relatively long fluorescence lifetime [3], which is advantageous for a laser system. Yb 3þ ion has a very simple energy level scheme and a 4f 13 shell that lacks one electron compared to a fitted shell. There are only two manifolds, the ground 2 F 7=2 state, and the excited 2 F 5=2 state, which are sepa- rated by approximately 10000 cm 1 and can gen- erally form a quasi-three-level system due to Stark splitting. Since only a single spectral band is available for pumping energy into the system, an InGaAs diode laser with pump wavelengths be- tween 0.9 and 1.1 lm has stimulated interest in diode pumped Yb 3þ lasers [4,5]. The family of YCa 4 OðBO 3 Þ 3 (YCOB) crystals belong to the monoclinic system with the space group Cm. These crystals have good chemical and physical properties in non-linear optical (NLO) and self-frequency-doubling (SFD) applications [6–8]. For example, YCOB crystal has a large transparent range, high non-linear optical coeffi- cient, high damage threshold, and the thermal conductivity of the crystals is much higher than 6 August 2002 Chemical Physics Letters 361 (2002) 499–503 www.elsevier.com/locate/cplett * Corresponding author. E-mail address: jhd@icm.sdu.edu.cn (H. Jiang). 0009-2614/02/$ - see front matter Ó 2002 Elsevier Science B.V. All rights reserved. PII:S0009-2614(02)00989-2