Spectroscopic Properties and Continuous Wave Laser Performances at 1064 nm of Nd3+: LuAG Transparent Ceramic

A transparent 2 at% Nd³⁺-doped Lu₃Al₅O₁₂ (LuAG) ceramic was fabricated by using tape-casting method and solid-state sintering technology. Based on the room temperature absorption spectrum, the three J–O intensity parameters were calculated with Judd–Ofelt analysis, and then, the radiative transition rates and branching ratios of transitions from ⁴<bold>F</bold>_3/2 manifold to the <inline-formula><tex-math notation="LaTeX">${}^4{{\rm {\mathbf I}}_{ \mathbf{{J}^{\prime}}}}$ </tex-math></inline-formula> (<inline-formula><tex-math notation="LaTeX">$\mathbf{{ J}^{\prime}} = \ 13/2,\;11/2,\;9/2$ </tex-math></inline-formula>) lower lying multiple manifolds were determined. The quantum efficiency of 80.4% was evaluated from the measured fluorescence lifetime and the radiative lifetime of the <inline-formula> <tex-math notation="LaTeX">${}^4{{\mathbf F}_{3/2\ }}$</tex-math></inline-formula> manifold state. Also, the inter-Stark energy levels of the <inline-formula><tex-math notation="LaTeX">$4{{{\mathbf I}}_{\boldsymbol{J^{\prime}}}}$</tex-math></inline-formula> manifolds were performed, and the peak emission cross sections of the <inline-formula><tex-math notation="LaTeX">${}^4{\mathbf{F}_{3/2\ }} \to {}^4{{{\mathbf {I}}}_{\mathbf{{ J}^{\prime}}}}$</tex-math></inline-formula> intermanifold transitions were determined. The total emission cross section for <inline-formula><tex-math notation="LaTeX">${}^4{\mathbf{F}_{3/2\ }} \to $</tex-math> </inline-formula> <inline-formula><tex-math notation="LaTeX">${}^4{\mathbf{I}_{9/2\ }}$</tex-math></inline-formula>, <inline-formula> <tex-math notation="LaTeX">${}^4{\mathbf{I}_{11/2\ }}$</tex-math></inline-formula>, and <inline-formula> <tex-math notation="LaTeX">${}^4{\mathbf{I}_{13/2\ }}$</tex-math></inline-formula> transitions was calculated to be <inline-formula><tex-math notation="LaTeX">$7.41 \times {10^{ - 20}}\ {{\rm c}}{{{\rm m}}^2}$</tex-math> </inline-formula>, <inline-formula><tex-math notation="LaTeX">$29.83 \times {10^{ - 20}}\ {{\rm c}}{{{\rm m}}^2}$ </tex-math></inline-formula>, and <inline-formula><tex-math notation="LaTeX">$10.53 \times {10^{ - 20}}\ {{\rm c}}{{{\rm m}}^2}$</tex-math></inline-formula>, respectively. Finally, under an 808 nm diode laser pumping, the continuous wave laser performances of the Nd:LuAG transparent ceramic were investigated.