The effect of residual porosity on the optical properties of Y$_3$Al$_5$O$_{12}$:Nd$^{3+}$ laser ceramics

The relationship between the residual porosity, linear optical loss coefficient, and sintering temperature-time regime has been studied for Y$_3$Al$_5$O$_{12}$:Nd$^{3+}$ (4 at%) laser ceramics. It is experimentally established that the linear optical loss coefficient linearly depends on the magnitude of residual porosity. The slope efficiency of laser generation reached a value of 31% in ceramics with a residual porosity on a level of 0.0016 vol% that was obtained by reactive sintering at 1750$^\circ$C for 12 h. The obtained results are important for optimization of the technology of Y$_3$Al$_5$O$_{12}$:Nd$^{3+}$ laser ceramics.