[en] Single crystals of SrAl/sub 12/O/sub 19/ doped with neodymium (the most common activator element in laser crystals) emit an intense luminescence. The purpose of this work was a detailed study of the absorption, fluorescence, selective excitation, polarization, and Raman spectra of SrAl/sub 12/O/sub 19/:Nd/sup 3+/ and construction of the energy-level diagram of the Nd/sup 3+/ ion in the crystal. SrAl/sub 12/O/sub 19/ single crystals were grown by the Czochralski method from the melt of 0.5- and 1-at. % Nd/sup 3+/ concentrations. The exact concentration of Nd/sup 3+/ in these crystals was determined using x-ray fluorescence techniques. SrAl/sub 12/O/sub 19/ is a hexagonal system which belongs to the space group P63//sub mmc/. The unit cell parameters are a = b = 5.562 +. 0.0022 A, c = 21.972 +. 0.005 A. Absorption spectra in the 0.5-5.5-μm range at 4.2, 77, and 293 K were recorded with a Hilger Manospek 600 Scanning monochromator and a Hilger-800 spectrophotometer. Fluorescence spectra were recorded using excitation with either an HBO 200 high-pressure mercury lamp or a quartz halogen lamp with a set of filters. The Raman spectra were obtained by 356.4-nm excitation from a krypton-ion laser. The scattered light was dispersed with a spectrometer. A cooled-type S-11 photomultiplier was used for detection followed by a Nicolet multichannel analyzer. The energy levels of the Nd/sup 3+/ ion having 4f/sup 3/ configuration have been tabulated for a number of host lattices. These energy levels arise from the crystal field splitting of the J manifold within the 4f shell extending up to 40,000 cm/sup -1/. Absorption transitions start from the levels of the ground (/sup 4///sub 9/2/) multiplet and terminate in various excited levels. Fluorescence spectra were observed for transitions from the /sup 4/F/sub 3/2/ manifold to the three lowest /sup 4/I multiplets