Spectroscopy and dynamics of Er3+:Y2SiO5 at 1.5 μm

We present the results of detailed site-selective spectroscopy performed on the I-4(15/2)<-> I-4(13/2) transition of Er3+:Y2SiO5 at 1.5 mu m. New determinations of the I-4(13/2) and I-4(15/2) crystal-field-level structure for the two crystallographically inequivalent Er3+ sites have been made. The fluorescence dynamics of the metastable I-4(13/2):Y-1 excited state was investigated, showing exponential decays for Er3+ at both crystallographic sites with fluorescence lifetimes of 11.4 ms for site 1 and 9.2 ms for site 2. Exceptionally sharp inhomogeneous absorption lines of 180, 390, and 510 MHz were observed in 0.0015% Er3+:Y2SiO5, 0.005% Er3+:Y2SiO5, and 0.02% Er3+:Y2SiO5 crystals, respectively. The g-values for the lowest energy I-4(15/2) (Z(1)) and I-4(13/2) (Y-1) doublets were measured to be 5.5 and 4.6 for site 1 and 15.0 and 12.9 for site 2 when the magnetic field was oriented along the crystal's D-1 axis.