Spectroscopic Properties and Diode Laser-Pumped Operation of Nd : YAl3(BO3)4 Crystal

Abstract

Subject classification: 42.55.Px; 78.20.Ci; S10.15Nd-doped yttrium aluminum borate, Nd x Y 1--x Al 3 (BO 3 ) 4 (NYAB), with large sizes and good optical quality has been grown by the flux method. When the Judd-Ofelt (JO) theory of parity-forbidden electric-dipole transitions of rare earth ions on non-centrosymmetric sites was applied to NYAB, it resulted in a good fit on absorption of the crystal. According to the JO theory, the fitted intensity parameters W t (t ¼ 2, 4, and 6) were calculated as 2.19 Â 10 --20 , 1.97 Â 10 --20 , and 3.10 Â 10 --20 cm 2 , respectively, with a root mean square deviation of 1.22 Â 10 --21 cm 2 . The emission properties of the excited 4 F 3/2 state have been studied, and the spectral parameters of NYAB crystal were compared with those of Nd x Gd 1--x Al 3 (BO 3 ) 4 (NGAB) crystal. A cw NYAB laser at 1.06 mm end-pumped by a high-power diode laser array has been demonstrated. A maximum output of 3.2 W at 1.06 mm has been achieved with an optical conversion efficiency of 29.1% and an average slope efficiency of 37.5%. It is found that these results approach those of Nd : YVO 4 crystal.