Crystal Growth and First-Principles Calculations of the Mid-IR Laser Crystal Dy³⁺:PbGa₂S₄

Abstract

A Dy3+-doped PbGa2S4 crystal with low phonon energy has been proved to be able to achieve the direct lasing of a mid-infrared laser. The single-crystal growth of Dy3+:PbGa2S4 was investigated in this work. On the basic of the high-purity polycrystalline material synthesized using a pressure-assisted method, a Dy3+:PbGa2S4 single crystal with φ 21 × 50 mm3 was successfully grown using the Bridgman method with a crucible–capsule technique. To understand the cleavage character of the PbGa2S4 crystal and get further insight into its electronic and phonon properties, the electronic, phonon, and mechanical properties of the PbGa2S4 host were investigated using first-principles calculations. PbGa2S4 exhibits not only a large electronic energy gap (2.76 eV) but also a low phonon energy (392 cm–1) due to the incorporation of heavy Pb atoms between the interlayers. The high-frequency phonon bands of PbGa2S4 are mainly contributed by the vibrations of Ga–S atoms in the layer network formed by GaS4 units. However, the weak Pb–S bonding connecting the alternating layers results in cleavage behavior of the PbGa2S4 crystal. We believe that the results of this paper could provide useful references for preparing or designing new chalcogenide hosts for mid-infrared lasers.

Enhanced Electron–Phonon Coupling Effect in Rare-Earth Borate Crystals Containing a “Quasi-Free-Oxygen” Motif

“…Rare-earth borate is an important optoelectronic functional material for applications in lasers, nonlinear optics, self-frequency doubling, etc. − Generally, RE ions have a special 4f n electronic configuration, where the 4f electrons are partially shielded by the outer 5s/5p orbitals . Thus, rare-earth borates usually have a reduced electron–phonon coupling effect compared to transition-metal-doped crystals, such as titanium sapphire and alexandrite. , In order to enhance such a weak coupling effect, we employed the anion-centered polyhedron strategy to evaluate the role of special anion vibrations on the 4f electron transition of a RE ion.…”

Optical and defect properties of mid-IR laser crystal Dy3+: PbGa2S4: a DFT and XPS study

“…The Pb/Ga/ S ratio was set to 1 : 2 : 4.04 (S-rich) and 1 : 2.02 : 4.04 (PbS : Ga 2 S 3 = 1 : 1.01 with excess 0.01 S, Ga 2 S 3 -rich), respectively. Our previous work 22 demonstrated that the doping concentration of 0.7 atom% led to the precipitation of Dy. Herein, the Dy doping concentration was set at the same 0.5 atom% in each group.…”

Recent Achievements in Lone-Pair Cation-Based Infrared Second-Order Nonlinear Optical Materials

“…Another case is Dy doping PbGa 2 S 4 . Crystals of Dy 3+ : PbGa 2 S 4 waere grown using the Bridgeman method, 124 and the 21 × 50 mm 3 size Dy 3+ : PbGa 2 S 4 single crystals could obtained.…”