Publication Details (including relevant citation information):
Modified Bridgman Growth of Oriented Er-Doped and Tm-Doped BaY2-xYbxF8 Crystals for Upconversion Laser Operation, J.J. Owen, A.K. Cheetham, N.A. Nighman, R.H. Jarman and R.J. Thrash, J. Opt. Soc Am. B, 11, 919 (1994).
High-quality, oriented crystals of BaY1.5Yb0.49Er0.01F8 have been grown under hydrogen fluoride from BaYYbF8 seed crystals by a gradient-freeze, stationary-solidification modification of the vertical Bridgman method. Emission spectra obtained parallel and perpendicular to  show marked anisotropy. The room-temperature upconversion laser threshold for the 4F9/2 -4I15/2 transition at 670 nm (with 960-nm pumping from a titanium:sapphire laser) with the output propagating perpendicular to  is approximately two thirds that when propagating parallel to , consistent with the differences observed in fluorescence emission spectra obtained for the two polarizations.
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