M. E. Innocenzi, R. T. Swimm, M. Bass, R. H. French, A. B. Villaverde, M. R. Kokta, "Room Temperature Optical Absorption in Undoped a-Al₂O₃",  Journal of Applied Physics, 67, 12,7542-46 (1990).

Room Temperature Optical Absorption in Undoped a-Al₂O₃

M. E. Innocenzi, R. T. Swimm, M. Bass, R. H. French, A. B. Villaverde, M. R. Kokta

    Optical absorption over a large dynamic range obtained by two different experimental techniques is reported for an undoped a-Al₂O₃ single crystal.  Absorption data are presented in two energy ranges: 0.94 - 3.5 eV and 4.5 to 8.6 eV.  Vacuum ultraviolet (VUV) absorption measurements were performed on three boules of Czochralski-grown single-crystal Al₂O₃ with differing starting material purities.  The inital powder purities were 99.99%, 99.999% and 99.999999%.  In addition to the VUV measurements, calorimetric absorption results obtained in the visible and near-infrared (ir) are presented.  An empirical formula obtained that provides an estimate of the absorption coefficient formthe near-ir to the VUV for undoped Al₂O₃ .  Detailed impurity analyses and sample histories are given for the optical quality a-Al₂O₃ utilized herein.  

Comment: (c) 2009 Roger H. French , frenchrh@lrsm.upenn.edu
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