Abstract of Publication No. 286
Room-temperature E||b and Eb
polarized excited-state absorption (ESA)
measurements on Mn6+ -doped crystals of BaSO4 in the 530 - 1800-nm spectral
region are reported. ESA transitions from the metastable 2T2 ligand-field state
to the lowest-energy ligand-to-metal charge transfer states involve two-electron
excitations and thus carry low intensity. A strong ESA band owing to the first
one-electron ligand-to-metal charge transfer transition peaks near 600 nm.
Between 700 and 900 nm, ground-state absorption is stronger than ESA, and
near-infrared pumping by laser diodes is thus possible. The stimulated-emission
cross section is larger than the ESA cross section over the whole range of
spontaneous emission. Our results indicate that tunable laser action between 920
nm and 1.6 mm should, in principle, be achievable. The effective peak
stimulated-emission cross section at 1100 nm is 3 × 10–19 cm2 .