Spectroscopy and lasing of a high Nd concentration Al-phosphate glass

An Al-phosphate glass containing Nd
³⁺
in concentrations ranging from
3 \times 10^{20}
to
2.7 \times 10^{21}
ions/cm
³
has been prepared and investigated spectroscopically. Different ways of measuring the
⁴
F
3/2
→
⁴
I
9/2
emission cross sections yield values between
1.96 \times 10^{-20}
and
2.7 \times 10^{-20}
cm
²
. At the highest concentration the decay time is 50 μs, while the radiative lifetime is estimated to be
\geq446 \mu
s. Lasing experiments were performed by pumping thin platelets of glass coaxially with a dye laser. Cross sections, losses, and differential efficiencies are derived from these experiments. The status of high concentration glasses versus stoichiometric Nd compounds is reviewed.