Spectroscopic Characteristics and Laser Performance of ${\rm Nd}{:}{\rm Y}_{1.8}{\rm La}_{0.2}{\rm O}_{3}$ Transparent Ceramics

(Nd
_x
Y
_0.9-x
La
_0.1
)
₂
O
₃
(x=0.005-0.04) transparent ceramics were fabricated by conventional solid-state processing. The radiative spectral properties of the ceramic samples were evaluated by fitting the Judd-Ofelt model with the absorption and emission data. (Nd
_x
Y
_0.9-x
La
_0.1
)
₂
O
₃
ceramics have broad absorption and emission bands with a radiative decay time of 328 μs. The absorption cross section at 806 nm and stimulated emission cross section at 1078 nm are calculated to be 1.53 ×10
^-20
and 5.22 × 10
^-20
cm
²
, respectively. The product of quantum efficiency and the ionic concentration (ηN) exhibited a peak value at 1.5 at% Nd
³⁺
ion concentration, while the lifetime decreases dramatically from 300 μs (0.5 at% Nd) to 49 μs (4.0 at% Nd). With 1.0 at% Nd:Y
_1.8
La
_0.2
O
₃
ceramics acting as a laser medium, continuous-wave output power of 1.03 W was obtained at 1079.5 nm under an absorbed pump power of 7.2 W, corresponding to a slope efficiency of 18.4%.