Structure of the terms of neodymium ions and the transfer of excitation energy in phosphate glasses

An experimental investigation was made of the structure of the energy terms of Nd³⁺ in phosphate laser glasses. The stimulated emission spectrum was determined for different concentrations of the active neodymium ions and for different frequencies within the spectral width of the luminescence line. The results of measurements indicated that the small spectral width of this line and the efficiency transfer of the excitation energy to the stimulated emission channel were due to a weak inhomogeneous broadening of the Stark components and a strong overlap of their Gaussian profiles.