Measurement of stimulated emission cross section and fluorescence branching ratio for Nd^3+ in sodium-β^″ alumina

Abstract

Room-temperature measurements of laser emission cross sections of Nd³⁺ ion in sodium-β″ alumina at 1.06 and 1.35 μm as well as the fluorescence branching ratios of ⁴F_3/2 to ⁴I_j manifolds are reported. A theoretical calculation based on absolute absorption measurements when a modified Judd–Ofelt phenomenological intensity analysis was used is reported. The cross sections thus determined are σ_1.06 = 3.1 ± 0.3 × 10⁻²⁰ cm² and σ_1.35 = 0.6 ± 0.1 × 10⁻²⁰ cm², respectively. The emission cross section at 1.06 μm was also determined by small-signal-gain measurements and was found to be in good agreement with the above value.