Excited state absorption and stimulated emission of Nd3+ in crystals.: Part I:: Y3Al5O12, YAlO3, and Y2O3

The excited state absorption spectra of the F-4(3/2) excited state of the Nd3+ ion in Y3Al5O12, YAlO3, and Y2O3 were measured in a continuous wave pump- and probe experiment in a wide spectral range from 850 nm (780 nm for Y3Al5O12) to 1500 nm. The cross sections were determined from a comparison with the emission spectra and the simultaneously measured ground state absorption bleaching. The strongest excited state absorption transitions were found in the 1220-1400 nm spectral region due to transitions to the (2)G(9/2) and (4)G(7/2) levels. The spectral positions of the measured transitions are in good agreement with the theoretically expected transitions calculated from the known Stark-level splittings.