Spectroscopic properties of Sm 3+ -doped lanthanum borogermanate glass

Abstract

a b s t r a c tUltraviolet-visible-near infrared (UV-vis-NIR) absorption and photoluminescence of (25 À x) La 2 O 3 -25B 2 O 3 -50GeO 2 glass series have been studied with different concentrations (x ¼0.1-1.0 wt%) of Sm 2 O 3 as an optically active dopant. The values of Judd-Ofelt (JO) parameters (Ω t ) follow the trend Ω 2 4Ω 4 4Ω 6 . Visible emission and decay times from the 4 G 5/2 level and its relative quantum efficiencies are measured. Intense reddish-orange emission corresponding to 4 G 5/2 -6 H 7/2 transition has been observed in these glasses under 488 nm excitation. A decrease in the quantum yield is observed with increasing Sm 3 þ ion concentration beyond 1% doping level.

Sm3+-Doped Molybdenum Gadolinium Borate Glasses for Orange Emission Laser Active Medium

“…The Ω 2 parameter is associated with the asymmetry around the Ln 3+ ion site, while Ω 4 and Ω 6 parameters are long-range parameters that can be related to the bulk properties of the glass such as the viscosity and basicity of the matrix. Moreover, Ω 6 depends on the 6 electron density of Ln 3+ ions [34]. In the present work, the value of the parameter Ω 4 is higher, refers to the glass matrix viscosity, and is affected by the vibronic transitions of the rare-earth ions bound to the ligand atoms [42].…”

“…are the Judd-Ofelt parameters, and ‖ ‖ 2 are the squared doubly reduced matrix elements of the unit tensor operator [31][32][33] of the rank = 2, 4, and 6, which are calculated from the intermediate coupling approximation for the transition to ′ ′ at the energy (cm −1 ) and are independent of the host. The experimental oscillator strengths ( exp ) of the transitions can be obtained by integrating the molar absorptivity ( ) at a wave number (cm −1 ) for each band as [34] exp = 4.32 × 10 −9…”

Effect of ligand field symmetry on upconversion luminescence in heat‐treated LaBGeO5:Yb3+, Er3+ glass

“…[6][7][8][9][10][11] Up to the present, most previous reports have focused on the nonlinear optical properties and the crystallization of LaBGeO 5 glass-ceramics (GCs), surface crystallized glass-ceramics (SCGCs) and ceramics containing LaBGeO 5 NCs and microcrystals. [12][13][14][15][16] In addition, highly efficient luminescent LaBGeO 5 glasses or crystals doped with Sm 3+ , Eu 3+ , Tb 3+ , or Tm 3+ ions have also been prepared, [17][18][19][20] while the effect of ligand field symmetry around rare earth (RE) ions on the upconversion (UC) luminescence in LaBGeO 5 glass, GCs, SCGCs, and ceramics co-doped with Yb 3+ , Er 3+ ions was rarely investigated. After heat treatment, the relocation of RE ions into a crystalline host must change their local site symmetric that may affect the selection rules of optical transition and thus the UC emission.…”

Synthesis and luminescence properties of Tb doped LaBGeO 5 and GdBGeO 5 glass scintillators

“…[11] In addition, germanate glasses have smaller maximum vibrational frequencies than silicate, phosphate, and borate glasses which increases the quantum efficiency of the rare-earth ions they are doped with; this gives the germanate glass potential to be a more efficient medium for optical lasers and fiber optical amplifiers. [12] Glass-based active dielectrics of LaBGeO 5 and nanocrystal embedded LaBGeO 5 glass ceramic are looking to replicate many favorable characteristics of single crystal such as ferroelectricity, high electrical resistivity, low dielectric constant, and low dielectric losses, but they are rarely studied for scintillator applications. [13] However, crystalline form LaBGeO 5 has been proven to be a successful host matrix for efficient light emission from Eu 3+ , Tb 3+ , and Tm 3+ .…”