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Pulsed laser ablation for volume fabrication of micro-optical arrays on large-area substrates

Laser micromachining by ablation is an established technique for the production of 2.5D and 3D features in a wide variety of materials. Mask projection techniques using excimer lasers have been used to fabricate microstructures on large panels where diamond turning and reflow techniques have reached their limits. We have developed 3D structuring tools based upon UV laser ablation of polymers to create large arrays of repeating micro-optical features. Synchronization of laser pulses with workpiece movement allows layer-by-layer growth of deep structures with outstanding repeatability. Here, we show recent developments in laser structuring with the combination of half-tone and binary mask techniques. Significant improvements in surface quality are demonstrated for a limited range of structures.