From elaboration to laser properties of transparent polycrystalline Nd-doped Y3Al5O12 and Y3ScAl4O12 ceramics: A comparative study

In this work, a comparative study of reactive sintering and optical properties of two laser ceramics Nd:Y3Al5O12 (Nd:YAG) and Nd:Y3ScAl4O12 (Nd:YS1AG) has been achieved.The reaction sequence from primary oxides to the final garnet phase has been first examined. It was shown that Sc2O3 additions lead to similar reaction sequence than for Nd:YAG ceramics. Nevertheless, because of its lower reactivity than Al2O3, Sc2O3 begins to react at higher temperatures, i.e. after the formation of the monoclinic intermediate phase Y4Al2O9. For temperatures of 1700 K, the pure garnet phase Nd:Y3Sc1Al4O12 was obtained.Spectroscopic and laser properties of 2 at.%Nd:YS1AG transparent ceramics were then determined. Laser slope efficiency of these ceramics was 13.5%. Broader laser emission bandwidth at 1061 nm and 1064 nm were also reported in Nd:YS1AG ceramics compared to Nd:YAG ones. Switching between these two main laser lines by increasing the pump power or ceramics temperature was also observed.

► The reaction sequence during vacuum sintering is similar for YAG and YSAG ceramics.
► Low diffusion coefficients of scandium in YSAG lead to high sintering temperature.
► Y2.94Nd0.06Sc1Al4O12 transparent ceramics show broad emission bandwidths.
► Y2.94Nd0.06Sc1Al4O12 fluorescence spectrum is temperature-dependant.
► Transparent Nd:YSAG and Nd:YAG ceramics can be used as solid-state lasers.