Effect of lithium-potassium mixed alkali on spectroscopic properties of Er3+-doped aluminophosphate glasses
Effect of lithium-potassium mixed alkali on spectroscopic properties of Er^3＋-doped aluminophosphate glasses

Er$^{3+}$-doped lithium-potassium mixed alkali aluminophosphate glasses belonging to the oxide system $x$K$_2$O-(15-$x$)Li$_2$O-4B$_2$O$_3$-11Al$_2$O$_3$-5BaO-65P$_2$O$_5$ are obtained in a semi-continuous melting quenching process. Spectroscopic properties of Er$^{3+}$-doped glass matrix have been analysed by fitting the experimental data with the standard Judd--Ofelt theory. It is observed that Judd--Ofelt intensity parameters ${\it\Omega}_ t (t= 2$, 4 and 6) of Er$^{3+}$ change when the second alkali is introduced into glass matrix. The variation of line strength $S_{\rm ed}$$^4$I$_{13/2}$,$^4$I$_{15/2}$] follows the same trend as that of the ${\it\Omega}_6$ parameter. The effect of mixed alkali on the spectroscopic properties of the aluminophosphate glasses, such as absorption cross-section, stimulated emission cross-section, spontaneous emission probability, branching ratio and the radiative lifetime, has also been investigated in this paper.