Re-study of Judd-Ofelt spectroscopic properties of Er3+-doped Gd3(Al, Ga)5O12 single crystal.

A previous paper [J. Lumin. 177 (2016) 219] has studied Judd-Ofelt spectroscopic properties of Er3+ (0.5 at%)-doped Gd 3 (Al, Ga) 5 O 12 garnet single-crystal, and reported the Judd-Ofelt intensity parameters Ω 2 = 1.47 × 10−20 cm2, Ω 4 = 1.38 × 10−20 cm2 and Ω 6 = 1.19 × 10−20 cm2. We have performed a re-study on the Judd-Ofelt spectroscopic properties of a similar garnet single-crystal Er3+(20 at%)-doped Gd 3 (Al 0.4 Ga 0.6) 5 O 12 , and obtained quite different values of Judd-Ofelt intensity parameters Ω 2 = (0.34 ± 0.11) × 10−20 cm2, Ω 4 = (0.48 ± 0.16) × 10−20 cm2 and Ω 6 = (1.05 ± 0.17) × 10−20 cm2. The quite different Ω t values given by two studies are mainly due to remarkably different absorption characteristics of Er3+ in the crystals employed in two studies, and factors that lead to quite different absorption characteristics are discussed. Another reason is that the hypersensitive transition at 380 nm was excluded from the Judd-Ofelt calculation in that paper, resulting in deviation of their result. Instead, all of the Er3+ absorption bands were included in our calculation, allowing to obtain more accurate Ω t values. Quite different Ω t values lead to considerable differences of relevant spectroscopic parameters, such as radiative rates and lifetimes of typical Er3+ emissions, for which the difference from each other is as much as three times. In addition, visible, near-infrared and mid-infrared fluorescence spectra and lifetimes of Er3+ in the studied crystal were measured, and the emission characteristics are discussed. • Er:Gd 3 (Al,Ga) 5 O 12 crystal was grown and its spectroscopic properties are studied. • Judd-Ofelt analysis was done and the result is compared with previously reported. • The Judd-Ofelt data obtained show large differences from the previously reported. • Main reason is large difference of Er3+ absorption features in two studies. • Sellmeier equation, lattice constant and segregation coefficient are presented. [ABSTRACT FROM AUTHOR]