Diffractive Optical Elements (DOEs) are micro-structed devices which modulate the amplitude, phase, or polarization of a light beam. In this work, we use femtosecond laser direct writing (FLDW) and lithography techniques to manufacture binary phase DOEs which produce high quality intensity distributions for different fs-laser micromachining. We have designed DOEs whose intensity pattern contains an intense square flap-top to produce ablation with two less intense areas, one before for heating and one after for polishing the material. Then, we manufactured these phase DOEs over a dielectric material, fused silica. The phase modulation is produced by the optical path difference due to the topography induced by ablation. Finally, we have analyzed the structure of these DOEs, i.e. their phase shift and roughness, reaching an average roughness of 49.15 nm and a phase shift of 1.014π, very close to the designed value, π. Moreover, we study the far-field diffraction patterns of the engraved DOEs, which are in good agreement with the theoretical ones.
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