Nanogratings and nanoholes fabricated by direct femtosecond laser writing in chalcogenide glasses.

We report on the fabrication of sub-wavelength nanostructures on the surface of As(2)S(3) chalcogenide glasses by appropriately controlling the irradiation condition of single-beam direct femtosecond laser writing. Nanogratings with a period of 180 nm were realized by multipulse irradiation. More importantly controllable nanoholes as small as 200 nm in diameter (one quarter of the illumination wavelength) were, for the first time, achieved in As(2)S(3) using direct laser writing by single-pulse irradiation.