Enhanced 2.7 μm emission from Er3+ doped oxyfluoride tellurite glasses for a diode-pump mid-infrared laser

Abstract

The influence of fluoride and shielding gas (O2 or Ar) on the physical and spectroscopic properties of Er3+ doped TeO2-ZnO-ZnF2 glass system is investigated. The larger electronegativity of F than O accounts for the gradual decrease of refractive index, density, and J-O parameters with increasing ZnF2. An analysis on Fourier transform infrared transmission spectra reveals that the absorption coefficient of OH− around 3 μm as low as 0.247 cm−1 can be achieved when 30 mol% ZnF2 containing sample is treated with Ar gas during glass melting process. The reduction of OH− groups combined with the low multiphonon relaxation rate (207 s−1) contributes to the enhanced emissions at 1.5 and 2.7 μm, along with prolonged lifetimes of 4I11/2 and 4I13/2 levels. A high branching ratio (17.95%) corresponding to the Er3+: 4I11/2 → 4I13/2 transition, the large absorption and emission cross section (0.44 × 10−20 cm2 and 0.45 × 10−20 cm2), and good gain cross section demonstrate that oxyfluoride tellurite glass could be a promising material for a diode-pump 2.7 μm fiber laser.

Mid-infrared emission and Raman spectra analysis of Er^3+-doped oxyfluorotellurite glasses

“…Moreover, the value of 18.63% for 50TF-1Er glass is better than that in Er 3 -doped TZF-30 glass [19] and Y2Er glass [9]. A high branching ratio provides a better opportunity to achieve 2.7 μm fluorescence from Er 3 ∶ 4 I 11∕2 → 4 I 13∕2 .…”

“…The addition of fluoride leads to a downtrend of covalence and, therefore, the decrease of Ω 2 . The Ω 6 is related to the rigidity of the host [19]. Tanabe et al [30] has reported that Ω 6 declines with the increment of local basicity in the ligands.…”

“…The large amount of TeO 2 is the main glass network former and provides the main thermal and optical properties. The bivalent alkaline-earth ions were introduced into the matrix to enhance the emission of rare-earth ions and play as the glass network modifier [19,20]. It has been reported that the addition of YF 3 into the matrix increases the viscosity of the melt and, finally, enhances the stability of the glass against crystallization [21].…”

Enhanced emission and spectroscopic properties in oxyfluoride glass ceramics containing LaOF:Er^3+ nanocrystals

“…Therefore, it is necessary to develop host materials with low phonon energy. So far, various materials have been widely investigated such as tellurite, germanate, fluoride glasses, single-crystals and GCs [7][8][9][10][11][12][13]. Among these materials mentioned above, GCs are one of the most important optical materials which combine the advantages of both glass (excellent fiber-drawing ability) and nanocrystals (strong crystal field).…”

Investigation of mid-infrared emission characteristics and energy transfer dynamics in Er3+ doped oxyfluoride tellurite glass

“…The large amount of TeO 2 is the main glass network former and provides the main thermal and optical properties. The bivalent alkaline-earth ions were introduced into the matrix to enhance the emission of rare earth ions and play as the glass network modifier1718. The introduction of large amount of F − ions decreases the phonon energy and depletes the OH − .…”