Damage channeling in femtosecond laser micro-structured SBN crystals

Near field optical microscopy has been used to evidence the existence of damage channeling in femtosecond micro-structured Nd:SBN crystals. The self-channeling of fs pulses produced a well-defined modification channel with rectangular cross-section, characterized by a different surface reflectivity, which sharply finishes with an optical breakdown structure. From the analysis of confocal micro-luminescence images, we have found that these permanent micro-structural modifications are accompanied by a large density of defects that act as luminescence inhibiting centers.