  The modification of single layer graphene due to intense, picoseconds
near-infrared laser pulses is investigated. We monitor the stable changes
introduced to graphene upon photoexcitation using Raman spectroscopy. We find
that photoexcitation leads to both a local increase in hole doping and a
reduction in compressive strain. Possible explanations for these effects, due
to photo-induced oxygenation and photo-induced buckling of the graphene, are
discussed.
