Glassy carbon layer formed in diamond-like carbon films with femtosecond laser pulses

We report the first observation, to our knowledge, of a glassy carbon (GC) layer modified from diamond-like carbon (DLC) films with femtosecond (fs) laser pulses. The GC layer, which is confirmed by Raman spectroscopy, is produced most efficiently at low laser fluence near the ablation threshold of the DLC films. This surface modification depends little on the laser polarization and wavelength used. The fs laser-induced GC layer should be a new thin-film material useful for a variety of engineering applications due to its characteristics similar to those of DLC and the additional properties inherent in GC.