Browsing by Author "Jewell, J. M."
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- Dynamics of the 5-EV optical-absorption in SIO2 glassTsai, T. E.; Jewell, J. M.; Sanghera, J. S. (AIP Publishing, 1993-06-01)The optical absorption at 5 eV in SiO2 glass was observed, using laser calorimetry, to change reversibly depending on the intensity of UV light. The generation and bleaching of an absorption band at 5 eV by two- and one-photon absorption processes, respectively, can explain these reversible changes. This observation supports the structural model of unrelaxed oxygen deficiency center for the 5 eV absorption band in silica.
- Separation of Intrinsic and extrinsic Optical-Absorption in a Fluoride GlassJewell, J. M.; Williams, Glen M.; Jaganathan, J.; Aggarwal, I. D.; Greason, P. (AIP Publishing, 1991-07-01)The contribution of impurity ions to the total optical absorption of a heavy metal fluoride glass has been determined at 532 and 1064 nm. Four ZrF4-BaF2-LaF3-AlF3-NaF glasses were prepared from various purity raw materials. The absorption coefficients of these glasses range from 0.92 to 45.4 x 10(-4) cm-1 at 1064 nm and from 7.43 to 11.1 X 10(-4) cm-1 at 532 nm as determined by laser calorimetry. The concentrations of Fe, Ni, Cu, and Co ions in each glass were determined by graphite furnace atomic absorption spectroscopy. These two measurements enable the absorption, due to transition metal ions to be differentiated from the intrinsic absorption of the glass. At 1064 nm, the absorption coefficient of these glasses is controlled entirely by the transition metal ion content. However, at 532 nm, the absorption by the transition metal ions accounts for 4-42% of the total absorption depending on impurity concentration. The intrinsic absorption of this fluoride glass calculated from these data at 532 nm is (7.69 +/- 0.99) X 10(-4) cm-1.