Femtosecond Laser Fabrication of Periodical Structures in Bulk of Transparent Dielectrics

We present results of experiments in development technology of precision micromachining of materials by focusing the femtosecond laser radiation into the bulk of transparent materials. Conditions of the realization and some key parameters of special regime of micromachining have been defined. It implements at certain ratio between scanning speed and repetition rate of femtosecond laser pulses. Under mentioned conditions the area destroyed by laser radiation moves along the optical axis near focus region in both directions, forming (during transverse scanning) in a bulk of the sample “periodical” structures. In results of our investigation we demonstrate precision cutting crystals, glasses, polymers and creating cylindrical cavities 1÷2 microns in diameter with aspect ratio more than 200 directed along the axis of laser beam.