Browsing by Subject "Optical waveguides"

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    Comparisons of tin depth profile analyses in float glass
    (Elsevier, 1998) Townsend P.D.; Can N.; Chandler P.J.; Farmery B.W.; Lopez-Heredero R.; Peto A.; Salvin L.; Underdown D.; Yang B.
    Data are presented showing the profile of tin diffusion during the production of float glass, by measuring non-destructively the refractive index profiles in the diffused layer. The optical waveguide modes give unequivocal evidence for an anomaly in the tin depth distribution. The results are compared with those from sectioning techniques, used in depth profiles determined by ion beam analyses and cathodoluminescence (CL). There is agreement between these methods which confirm the presence of a maximum in the tin concentration below the surface which had been in contact with the tin bath (this had been linked by Mössbauer data to a rise in the Sn4+ concentration). The ion beam analyses record different depth profiles for Si, Na and Ca. The Sn4+ feature increases the refractive index, as does the diffusion of Sn2+. The index becomes constant at large tin concentrations. We suggest that Sn4+ is linked to CL emission at 2.68 eV and Sn2+ to the 1.97 eV CL emission. Iron impurities give a 1.73 eV signal. Contrary to earlier suggestions, we propose that the luminescence associated with the presence of tin arises from intrinsic defects stabilised by the tin, not from tin acting directly as a luminescence site. © 1998 Elsevier Science B.V.
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    Nonlinear optical absorption of ZnO doped with copper nanoparticles in the picosecond and nanosecond pulse laser field
    (OSA - The Optical Society, 2005) Ryasnyansky A.; Palpant B.; Debrus S.; Ganeev R.; Stepanov A.; Can N.; Buchal C.; Uysal S.
    The nonlinear absorption of nanocomposite layers based on ZnO implanted with Cu+ ions with an energy of 160 keV in implantation doses of 1016 and 1017 ions/cm2 was investigated. The values of the nonlinear absorption coefficient were measured by the Z-scan method at a wavelength of 532 nm by use of nanosecond and picosecond laser pulses. Possible optical applications of these materials are discussed. © 2005 Optical Society of America.