Developments in Ceramic Materials Research

84
Fluorescence, a.u.
I transfer , a.u.
1
0.1
0.01
0.001
1
0.1
T. T. Basiev, V. A. Demidenko, K. V. Dykel’skii et al.
Gd 2 O 2 S:Nd 3+
2
0 100 200 300 400 500 600 700
time, μs
time, μs
1
0.1w.%
τ=107 μs
0.5 w.%
a)
Gd 2 O 2 S:Nd 3+ (0.5 w.%)
0 50 100 150 200 250 300
Figure 29. Fluorescence kinetics decay of the 4 F 3/2 manifold of the Nd 3+ ion in the Gd 2O 2S:Nd 3+
(0.1 wt%) (curve 1—a) and Gd 2O 2S:Nd 3+ (0.5 wt%) (curve 2—a) crystal ceramic samples measured
under 893.5 nm laser excitation at 1.08 μm fluorescence detection; and the energy transfer kinetics from
the same manifold of the Nd 3+ ion in the Gd 2O 2S:Nd 3+ (0.5 wt%) ceramic sample—b.
It should be pointed out that the 4 F3/2 manifold decay times found are much shorter than
those for commonly used laser crystals such as YAG:Nd 3+ (τ=230 μs) [59] and YLF:Nd 3+
(τ=520 μs) [60] and is comparable with the lifetime measured in the PbCl2:Nd 3+ (τ=119 μs)
[61]. The main reason for this is the high refractive index n=2.2 for the oxysulfide optical
ceramics [35]. This leads to an increased radiative rate A due to higher photon density of the
states and high polarizability of the surrounding medium in Gd2O2S:Nd 3+ . For PbCl2:Nd 3+ the
refractive index n is also high (n=2.2) in comparison with YLF: Nd 3+ (n=1.62) and YAG:Nd 3+
(n =1.82).
b)