Growth process and optical investigations of Nd:NaGd (MoO4)2crystals with varying content of Nd and Gd

In this paper, [NaGd 1‐ xNdx](MoO 4 ) 2 crystals with x = 0.005–0.05 were grown by Czochralski method at 950 ℃ for 10 hours and subsequently characterized by absorption spectroscopy and fluorescence spectroscopy. The intensity parameters of Nd 3+ were calculated by Judd‐Ofelt theory, and the relationship between the parameters and Nd 3+ concentration was analyzed. The results show that with the increasing Nd 3+ concentration, the oscillator strength, stimulated emission cross‐section, Ω t and spontaneous transition probability decrease slightly, while the fluorescence lifetime decreases significantly. However, the fluorescence branching ratio is almost unchanged with the increasing Nd 3+ concentration. The [NaGd 1‐ x Nd x ](MoO 4 ) 2 crystal with ( x = 0.01) possesses the highest quantum efficiency of 88.98%, a good fluorescence line‐width of 23 nm, a large value of σ em· τ f up to 0.55 × 10 −22 cm 2 ·s and a stimulated emission cross‐section up to 3.747 × 10 −19 cm 2 for the transition from 4 F 3/2 to 4 I 11/2 at 1064 nm. Test results indicate that [NaGd 1‐x Nd x ](MoO 4 ) 2 crystals are an excellent gain media for the solid state laser system.