Polarized fluorescence spectra produced by site-selective excitation, and conventional polarized absorption spectra were obtained forTm3+andEr3+ions individually incorporated into single crystals of strontium fluorapatite,Sr5(PO4)3F,also known as SFAP. Substitution of the trivalent rare earth ion for divalent strontium was achieved by passive charge compensation during Czochralski growth of the fluorapatite crystals. Spectra were obtained between 1780 and 345 nm at temperatures from 4 K to room temperature on crystals having the hexagonal structure[P63/m(C6h2)].The polarized fluorescence spectra due to transitions from multiplet manifolds ofTm3+(4f12),including1D2,1G4,and3H4to manifolds3H6(the ground-state manifold),3F4,3H5,3H4,and3F3were analyzed for the details of the crystal-field splitting of the manifolds. Fluorescence lifetimes were measured forTm3+transitions from1D2,1G4,and3H4at room temperature and from1G4at 16 K. Results of the analysis indicate that the majority ofTm3+ions occupy sites havingCssymmetry. A point-charge lattice-sum calculation was made in which the crystal-field components,Anm,were determined assuming that trivalent thulium replaces divalent strontium in the metal site havingCssymmetry. Results support the conclusion that the nearest-neighbor fluoride (F−) is replaced by divalent oxygen(O2−),thus preserving overall charge neutrality and local symmetry. Crystal-field splitting calculations predict energy levels in agreement with results obtained from an analysis of the experimental data. By varying the crystal-field parameters,Bnm,we obtained a rms difference of7 cm−1between 43 calculated and experimental Stark levels forTm3+(4f12)in Tm:SFAP. Absorption and fluorescence spectra are also reported forEr3+ions in Er:SFAP. Measurement of the temporal decay of the room temperature fluorescence from the4I11/2and4I13/2manifolds yielded fluorescence lifetimes of 230±20 &mgr;s and 8.9±0.1 ms, respectively. The experimental Stark levels obtained from an analysis of the spectroscopic data were compared with a crystal-field splitting calculation. The initial set ofBnmparameters forEr3+(4f11)was established from the three-parameter theory and the final set ofBnmparameters obtained forTm3+(4f12)in Tm:SFAP. The best overall agreement between calculated and experimental Stark levels is8 cm−1for 48 Stark levels, representing 12 observed multiplet manifolds ofEr3+(4f11)in Er:SFAP. ©1997 American Institute of Physics.