Enhanced 573 nm yellow emissions of Dy^3+ via Tb^3+ deactivation in Na_2Gd_4(MoO_4)_7 crystal

Pr3+ deactivation effect to Tm3+ at ∼1.5 μm emission in Bi4Ge3O12 crystals grown by the micro-pulling-down method

“…where τTm/Pr and τTm are the lifetime of Tm 3+ : 3 F4 level in Tm:BGO crystals with and without Pr 3+ co-doping, respectively. With increasing the Pr 3+ doping concentration from 0.1 at.% to 0.5 at.%, the energy transfer efficiency increased from 78.0% to 93.6%, which is much higher than that in Tm,Tb:GdScO3 (35.7% [7]) and Tm,Tb:GLSO (74.4% [6]), indicating that Pr 3+ ions can efficiently quench the lower laser level of the Tm 3+ : 3 F4. Moreover, the upper laser level ( 3 H4) to lower laser level ( 3 F4) fluorescence lifetime ratio in Tm,Pr:BGO crystals are calculated and are also listed in Table 1.…”

“…The energy transfer efficiency (η) of Tm 3+ : 3 F4 level to Pr 3+ : 3 F2 level can be evaluated by the following formula [6]:…”

“…Unfortunately, the self-terminating transition ( 3 H4 → 3 F4) of Tm 3+ ions, namely, the upper level ( 3 H4), has a shorter lifetime than the lower one ( 3 F4), almost extinguishing the probability of population inversion for lasing at around the 1.5 μm wavelength. In order to achieve intense Tm 3+ : 3 H4 → 3 F4 NIR emissions for practical laser operation, co-doping deactivating ions, such as Tb 3+ [4][5][6][7][8][9], Ho 3+ [8]and Eu 3+ [9,10], is an effective way to depopulate the Tm 3+ : 3 F4 level for population inversion and create a desirable fluorescence lifetime ratio. Moreover, Tm 3+ lasers emitting at around 1.5 μm have been demonstrated in Tm 3+ /Ho 3+ co-doped YLiF4 crystal [11], Tm 3+ /Tb 3+ co-doped YLiF4 crystal [12] and Tm 3+ /Ho 3+ co-doped tellurite glass microsphere [13].…”

Crystal Growth, Property Investigation, and the Deactivation Effect of Tb3+ in Dy3+/Tb3+ Codoped LiYF4 Crystals: Promising Crystals for All-Solid-State Yellow Lasers

“…In this work, the Sellmeier equation calculating the refractive index used in the JO is from ref , and the values of squares of the reduced matrix elements |U ( t ) | 2 are from refs − . The Ω 2eff of Dy 3+ in Dy,Tb:YLF (Ω 2‑Dy,Tb = 5.01 × 10 –20 ) is larger than that in Dy:YLF (Ω 2‑Dy = 2.32 × 10 –20 ); the Ω 2 value will be affected by the crystal structure and coordination symmetry, and it will increase with a decrease in symmetry, − indicating that the codoping of Tb 3+ ions will reduce the local symmetry around the site of Dy 3+ ions in the YLF crystal and enhance yellow laser emission. Because the crystal field surrounding the Dy 3+ ion will have a great influence on the transition of particles between energy levels, especially the 4 F 9/2 → 6 H 13/2 transition, the corresponding yellow laser emission will be greatly enhanced when Dy 3+ is located in lower symmetry sites. , We also calculated the radiative transition rate A average (J → J′), the fluorescence branching ratio β­(J → J′), and the radiative lifetime τ rad of the excited states 4 F 9/2 of Dy 3+ ions, as shown in Table .…”

Efficient continuous-wave and passively Q-switched operation of yellow dysprosium lasers

“…The absorption and emission of Dy 3+ ions are low due to the spinforbidden transition in the visible range. Considering the energy levels of Dy 3+ and Tb 3+ ions together, efficient energy transfer from Dy 3+ : 6 H13/2 to Tb 3+ : 7 F4 can greatly facilitate the possible population inversion from Dy 3+ : 4 F9/2 to Dy 3+ : 6 H13/2, which may enhance the yellow fluorescence emission 1,7,8 . Hence, crystals and fibers based on Dy 3+ and Tb 3+ ions co-doped materials have been largely developed in recent years.…”