Ultrafast laser beam shaping for material processing at imaging plane by geometric masks using a spatial light modulator. (July 2015)

• Record Type: Journal Article
• Authors: Kuang, Zheng; Li, Jiangning; Edwardson, Stuart; Perrie, Walter; Liu, Dun; Dearden, Geoff
• Is Part Of: Optics and lasers in engineering. Volume 70(2015)
• Page Start: 1
• Page End: 5
• Publication Date: 2015-07
• Subjects: Ultrafast laser -- Beam shaping -- Material micro-processing -- Geometric mask -- Spatial light modulator; Lasers in engineering -- Periodicals; Optical measurements -- Periodicals; Optics -- Periodicals; Lasers en ingénierie -- Périodiques; Mesures optiques -- Périodiques; Optique -- Périodiques; 621.36605
• DOI: 10.1016/j.optlaseng.2015.02.004
• Languages: English
• ISSNs: 0143-8166

Abstract

Abstract: We have demonstrated an original ultrafast laser beam shaping technique for material processing using a spatial light modulator (SLM). Complicated and time-consuming diffraction far-field phase hologram calculations based on Fourier transformations are avoided, while simple and direct geometric masks are used to shape the incident beam at diffraction near-field. Various beam intensity shapes, such as square, triangle, ring and star, are obtained and then reconstructed at the imaging plane of an f-theta lens. The size of the shaped beam is approximately 20 µm, which is comparable to the beam waist at the focal plane. A polished stainless steel sample is machined by the shaped beam at the imaging plane. The shape of the ablation footprint well matches the beam shape. Highlights: An ultrafast laser beam shaping technique for material processing is demonstrated. Arbitrary beam intensity shapes can be created using a spatial light modulator. The beam shape is obtained at near field by geometric masks. The shape reconstructed at imaging plane has a size comparable to the beam waist. The machined footprint on a metallic sample has the corresponding beam shape.