$^4T_2\to{}^4A_2$ transition in the luminescence spectra of Mn$^{4+}$ ion in gadolinium gallium garnet at intense laser pumping

The Mn$^{4+}$ $^4T_2\to{}^4A_2$ transition was observed in the luminescence spectrum of Gd$_3$Ga$_5$O$_{12}:{}$Mn$^{4+}$ at intense laser pumping. It is shown that the $^4T_2\to{}^4A_2$ transition becomes more intense than $^2E\to{}^4A_2$ because of an increase in the role of induced transitions with increasing pump power. This process is most efficient in the region of strongest overlap between the $^2E\to{}^4A_2$ and $^4T_2\to{}^4A_2$ bands, where it leads to strengthening of the zero-phonon line of the latter at $694$ nm. It is assumed that GGG${}:{}$Mn$^{4+}$ can be used as an active material in tunable lasers.