Tailoring light pulse amplitudes for optimal laser processing and material modification

A laser processing technique has been developed for laser direct-write patterning tools that enable site-selective material modification processes on the scale of the laser spot size. The technique controls the delivery of laser energy for optimal laser processing by the dynamic regulation of individual laser pulses to form a prescribed sequence of amplitude-modulated laser pulses. This sequence of amplitude-modulated pulses, called a pulse-script, is then administered to each laser spot size area along a tool path regardless of the stage motion velocity. In our current configuration, up to 32 different pulse-scripts can be independently selected and applied during direct-write patterning at motion velocities exceeding 400 mm/s. The novel processing technique seamlessly merges information that depicts the tool path pattern in Cartesian space with the type of material modification and transformation processes that are desired at each laser spot location. This paper describes the fundamental and functional aspects of this new technique. As a demonstration of the technique, a series of variable wavelength attenuators and embedded cutoff filters have been fabricated in a photo-structurable glass ceramic material.