Optical spectroscopy of Nd-doped borate glasses

Optical absorption, luminescence excitation and emission spectra as well as luminescence kinetics of the Nd
³⁺
centres in glasses with Li
2
B
4
O
7
:Nd, LiCaBO
3
:Nd, and CaB
4
O
7
:Nd compositions containing 0.5 and 1.0 mol. % Nd
2
O
3
have been investigated and analyzed. Using Judd-Ofelt theory oscillator strengths (f) and phenomenological intensity parameters Ω
t
(Ω
2
, Ω
4
, and Ω
6
) for all investigated glasses were determined. Radiative transitions rates (W
r
), radiative lifetimes (τ
rad
), and branching ratios (β) for Nd
³⁺
centres have been calculated. Measured lifetimes for Nd
³⁺
centres in the
⁴
F
3/2
emitting level are compared with those calculated and quantum efficiency (η) have been estimated.