Radiative transition probabilities within the 4 3ground configuration of Nd:YAG

The absolute intensities of 20 absorption bands between 2.5 and 0.25 μ have been measured for Nd:YAG at room temperature. These bands are forced electric dipole transitions between the⁴ ground manifold and 34 excited manifolds of the Nd³⁺ion. The transition intensities have been accounted for in terms of three phenomenological parameters with an rms error of 10 percent. The intensity parameters are used to evaluate the line strengths for excited-state absorption from the metastable⁴ manifold. Significant line strengths are predicted at wavelengths near 1.06 and 1.35 μ, suggesting the possibility of radiative depumping of the⁴ upper laser level via the stimulated emission field.