Origin of the refractive-index increase in laser-written waveguides in glasses
- Corning Inc., Corning, New York 14831 (United States)
We present firm evidence that the mechanism for the refractive-index increase in fused silica caused by irradiation with ultrafast intense laser pulses is the densification of glass. This conclusion is based on the correlation observed between the refractive-index values in waveguides in silica produced by focused femtosecond laser pulses and the shift of the central frequency of {omega}{sub 4} (TO) band (Si-O stretching mode) in micro-Raman spectra. These data were compared with the relation of the Raman shift to density and to refractive index changes in glasses modified by high pressure or irradiation. We conclude that the measured refractive-index increase in silica waveguides can be explained by densification of glass and exclude other hypothesis such as fictive-temperature effect, color center formation, etc.
- OSTI ID:
- 21133993
- Journal Information:
- Journal of Applied Physics, Vol. 103, Issue 6; Other Information: DOI: 10.1063/1.2888561; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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