  We report on a self-organized process initiated on a
potassium-tungsten-tellurite glass surface under repetitive femtosecond laser
irradiation in a regime where cumulative effects lead to a localized melting.
Specifically, we show that self-organized periodic patterns consisting of
parallel nanoplanes perpendicular to the laser polarization are forming and
extending beyond the zone under direct laser exposure. Examination of the
modified regions revealed a phase change from a glassy tellurium-oxide to a
crystalline elemental tellurium. In addition, we observe that this
self-organization process, associated with elemental redistribution and
deoxygenation, is triggered by the optical-field strength. We suggest that
early self-organized nanostructures formed by a local-field enhancement is
subsequently reinforced by a metallization event in an open-air atmosphere.
