Permanent birefringence patterns engraved in fused silica with infrared femtosecond laser pulses

Summary form only given. Ultrashort laser pulses have proven well-suited for the engraving of modifications in the optical properties of transparent materials, with controllable microscopic dimensions. We report on a new such effect, the permanent inscription of birefringent grooves with a size of a few pm inside thin fused silica platelets. They were obtained by tight focusing of the output of a Ti:sapphire laser delivering ultrashort infrared pulses at 200 kHz repetition rate. Each groove was engraved by displacing the laser spot at constant speed in a direction parallel or perpendicular to its polarization vector. As an example, a periodic structure of 50 grooves, separated by 20 /spl mu/m of unmodified material has been realized.