Abstract
Raman microscopy and refractive near-field profilometry were used to analyze waveguides written in Yb-doped Kigre QX glass under the low repetition-rate (noncumulative-heating) regime. It was found that femtosecond-laser induced refractive index change was due to an increase in the proportion of Q1 P-tetrahedra and the associated increase in the polarizability of the glass. The role of color center formation and removal in this process is clearly defined, phosphorous-oxygen hole centers (POHCs) and PO3- ions form as a result of P-O bonds being broken during the modification process, and the subsequent removal of POHCs give rise to the increased proportion of Q1 P-tetrahedra. This result, when compared to other studies undertaken in the cumulative-heating regime, show conclusively that the mechanism of refractive index change in a particular type of glass can be very different, depending on the irradiation conditions.
Original language | English |
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Article number | 033110 |
Pages (from-to) | 033110-1-033110-5 |
Number of pages | 5 |
Journal | Journal of Applied Physics |
Volume | 108 |
Issue number | 3 |
DOIs | |
Publication status | Published - 1 Aug 2010 |