method with reference to texturing of a magnetic disk as an example the method uses a laser short pulses from the laser beam are serially sliced out for example by collecting the first order diffraction from two acousto optic modulators in series the beam path length for each beam is identical and the active optics are the same in order to produce equal texturing on both sides of the substrate such as both sides of a magnetic disk the invention uses two acousto optic modulators referred to as mod a and mod b arranged in a series to slice out 34 equal 34 laser pulses from a 34 mother 34 laser beam a master square wave oscillator of 50 50 duty cycle is generated to make this possible a 20 khz rep rate is suitable for the oscillator mod a and mod b are triggered by two independent pulse trains each triggered by the rising and falling edges of the oscillator respectively all pulse widths are less than half of the master oscillator 39 s period assuming a 20 khz rep rate for the oscillator this means that the pulse width for texturing the glass substrate typically is less than ten microseconds a first order diffracted beam is collected from each of mod a and mod b there is some beam divergence in the two laser beams so it is necessary to make the beams equal in propagation distance before each beam.