OPTICAL-PROPERTIES OF ND3-CRYSTAL SRAL12O19( IN SINGLE)

The spectroscopic characteristics of triply ionized neodymium in Sr1-x NdxAl12-xMgxO19 for x = 0.03 and 0.15 are presented; one Mg2+ ion per Nd3+ is required for charge compensation. Crystals of this composition are optically uniaxial, with absorption and emission depending strong ly on polarization. The room-temperature fluorescence lifetime is 430 mu s for x = 0.03 and 280 mu s for x = 0.15. The main absorption and e mission peaks can be fit by assuming the Nd3+ ion substitutes for Sr2 in a site of D-3h point-group symmetry. A crystal-field Hamiltonian o f D-3h symmetry is used to fit the data. A best-fit rms deviation of 4 .2 cm(-1) is obtained between 32 experimental and theoretical energy l evels for the 13 lowest J-multiplets of the 4f(3) electronic configura tion of Nd3+ with the following crystal field parameters: B-20 = -202. 8 cm(-1), B-40 = 632.7 cm(-1), B-60 = -1752 cm(-1), and B-66 = -1180 c m(-1). The stimulated emission in the F-4(3/2) --> I-4(9/2), F-4(3/2) --> I-4(11/2), and F-4(3/2) --> I-4(13/2) channels peaks at 902, 1049. 7, and 1306.5 nm, respectively, and in all cases it is sigma-polarized . The respective spectroscopically determined stimulated emission cros s sections for these wavelengths are 3.7 x 10(-20), 1.1 x 10(-19), and 2.6 x 10(-20) cm(2). The best absorption band for diode-laser pumping is centered at 798 nm, with an absorption coefficient of 14 cm(-1) fo r x = 0.15 and a full-width at half-maximum of 2.5 nm.