Doping Concentration Of Tm3 Research Articles

Deciphering the Microstructure and Energy-Level Splitting of Tm3+-Doped Yttrium Aluminum Garnet.

Thulium-doped yttrium aluminum garnet (Tm:YAG) is an important solid-state laser crystal. The energy-level splitting within it is still an unresolved problem. Here, we perform a theoretical study on the microstructure of Tm3+-doped YAG using the CALYPSO structure search method in conjunction with first-principles calculations. The calculated results show that the 4.16% doping concentration of Tm3+ impurity causes an obvious structural distortion of YAG crystal, forming an orthorhombic phase in C222 symmetry. On the basis of our developed WEPMD method, we obtain a new and complete set of free-ion and crystal field parameters by a good fit (with proper irreducible representations) to 69 observed energy levels and determine the exact energy-level splitting of Tm3+ in YAG. The calculated Stark levels and electric dipole transitions are in excellent agreement with the measured data and similar theoretical calculations. Some promising emission lines between 3F3, 3F2, 1D2, and 1I6 states are presented. These findings offer fundamental insights and practical tools for further exploration of the structural and electronic properties of other transition-metal-doped YAG crystal.

The preparation of Yttrium Aluminosilicate (YAS) Glass Fiber with heavy doping of Tm3+ from Polycrystalline YAG ceramics

AbstractYttrium aluminosilicate (YAS) glass core fibers with different doping concentration of Tm3+ were fabricated by a “Melt‐in‐Tube” method from YAG polycrystalline ceramics. The effect of Tm3+ concentration on the spectroscopy of YAG ceramics and laser performance of YAS fibers were discussed. A homemade linear all‐fiber laser based on the obtained 15% Tm3+‐doped YAS fiber shows an optimized slope efficiency of 12.8%. The YAS fibers have been proven to be practical to achieve extremely high Tm3+ doping concentration and are a promising option for the 2.0 μm laser.

Infrared optical characterization and energy transfer of Na5Lu9F32 single crystals co-doped with Er3+/Tm3+ grown by Bridgman method

This paper reported on successful preparation of Na5Lu9F32 single crystals co-doped with ∼2mol% Er3+ and various Tm3+ concentrations from 0.7mol% to 3.2mol% by Bridgman method. The J-O intensity parameters of Er3+ were calculated and analyzed according to the absorption spectra. The fluorescence decay curve at Er3+:4I13/2 level was measured to investigate the luminescent properties of the Er3+/Tm3+ co-doped Na5Lu9F32, and the energy transfer process between Er3+ and Tm3+. An intense 2.7μm emission was achieved with Tm3+ ions sensitizing Er3+ ions under the 800nm LD pumping. The maximum emission intensity at 2.7μm was obtained at about 3.2mol% doping concentration of Tm3+ when the concentration of Er3+ ions was fixed at ∼2mol% in the current research. The calculated maximum value of emission cross section at 2.7μm was 2.22×10−20cm2, and energy transfer efficiency from Er3+:4I13/2 to Tm3+:3F4 was 78%. The electric dipole-dipole interaction was dominant for the energy transfer from Er3+ to Tm3+ ions by using Inokuti-Hirayama’s model.

Concentration-controlled emission in LaF3:Yb3+/Tm3+ nanocrystals: switching from UV to NIR regions

The homogeneous LaF3:Yb3+/Tm3+ nanocrystals (NCs) with an average diameter of 5 nm and different doping concentrations (Yb3+: 2–20%, Tm3+: 0.2–1.5%) were synthesized by a simple solvothermal approach. Their emission spectra, luminescent dynamics, and power-dependence of up-conversion (UC) photoluminescence were investigated in detail. Under 980 nm excitation, as-synthesized NCs exhibited interesting emission properties: a broad range of photoluminescence spanning from the ultraviolet (UV, ∼330 nm) to near infrared (NIR, ∼1700 nm) region, as well as the tunable relative intensity of different excited states. These unique UC or down-conversion (DC) emission behaviors were strongly influenced by the doping concentration of Tm3+ and Yb3+ ions within LaF3 NCs. With the increase of the concentration ratio between Yb3+ and Tm3+ ions, the NIR emissions were highly suppressed, but the UV and visible emissions increased quickly. The result demonstrated that such concentration effect was mainly originated from two mechanisms: one was the competition mechanism among the different intermediate exciting levels such as 3F4, 3H4, 1G4 and 1D2, and the other was the cross-relaxation mechanism between the Tm3+ ions. By optimizing the concentration of Tm3+ and Yb3+ ions, multi-photon UC or DC luminescence properties of LaF3:Yb3+/Tm3+ NCs could be facilely tuned from UV to NIR, which will be helpful for their further applications in the field of sensing, imaging, labeling, lighting and displays, etc.