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Laser‐induced periodic surface structures (LIPSS) have become an important avenue towards surface nanopatterning and certain device applications due to their subwavelength feature size and versatility with different materials. However, the uncontrollable non‐uniformity in achievable nanostructures presents a limit towards its practical application. Here, a robust approach is proposed to obtain controllable nanostructures with long‐range order based on a new insight into one of the electromagnetic origins of nonuniformity of LIPSS, namely a half‐periodic mismatched optical enhancement (h‐MOE) effect. The h‐MOE effect originates from the interference enhancement of surface plasmon polaritons (SPPs) located between tips of every two adjacent ripples in laser scanning process. It is found that LIPSS can be self‐aligned and highly controllable if the h‐MOE effect is elaborately modulated through designed laser scanning strategies especially sequential scanning paths. The new laser nanopatterning approach based on h‐MOE demonstrates controllable patterning ability to theoretically infinitely large‐area super‐straight gratings, orientation‐controllable gratings, and half‐periodic mismatched nanohole arrays. [ABSTRACT FROM AUTHOR]

• Efficiently fabricating hierarchical nanotextured microgrooves through hybrid laser processing. • Producing uniform 1D nanogratings and 2D nanoholes on V-shaped microgrooves. • Laser interference and laser-SPPs interference contribute to the formation of those nanostructures. • Those nanostructures can engrave into many microgrooves within one scanning process. Functional surfaces with hierarchical micro-/nanostructures play a vital role in improving performances in emerging fields over the past decades. In this work, we propose a hybrid manufacturing method for efficiently fabricating hierarchical nanotextured microgrooves by combining fly cutting and femtosecond laser nanopatterning. Nanostructures, including nanogratings and nanoholes, can be uniformly generated in a V-shaped groove by controlling laser polarization. We experimentally study the influence of the laser parameters (laser fluence and effective pulse number) to investigate the morphological evolution of nanostructures in the V-shaped groove under laser irradiation. By theoretical calculations and analyses, we find that the interference between the incident and reflected laser is helpful for ablating the nanogratings. In addition, this interference can also couple with the laser-SPPs (surface plasmon polaritons) interference and form nanoholes. The results enrich the diversity of achievable laser-induced periodic surface structures on complex surfaces and provide a new way to efficiently fabricate large-area hierarchical micro-/nanostructures at low cost. [ABSTRACT FROM AUTHOR]

• Multiscale structures were fabricated by hybrid vector beams for the first time. • Shapes of multiscale patterns can be controlled by designing state of polarization. • Polarization ellipticity at arbitrary azimuth angle of hybrid vector beam is deduced. • LIPSS fabricated by hybrid vector beams are rotational symmetric with 90° rotation angle. • Circular polarized laser induces the formation of nanoparticles. Hybridly polarized beam is a new type of vector beam different from conventional cylindrical vector beam. In our work, we present a simple and effective method to generate hybridly polarized beams by using a cascade of a super structured polarization converter and a quarter-wave plate. The transformation of light field was analyzed by using Jones vector and Jones matrix, and the Stokes parameters of the generated vector beams were measured to verify the states of polarization. Various novel multiscale micro-/nanostructures were fabricated on surfaces of 4H-SiC by using the hybrid vector beams, which are different from that induced by linearly polarized beam or conventional cylindrical vector beam. Experimental results show that the multiscale characteristics can be adjusted with a high degree of freedom by designing states of polarization. This research provides a new idea for preparation of multiscale micro-/nanostructures that may be useful in the fields of nano-/micro-electromechanical systems, thermal photovoltaics, and thermal management. [ABSTRACT FROM AUTHOR]

The surface modification by ultra-fast laser could regulate the mechanical properties of hard and brittle materials. Since silicon carbide (SiC) is too hard to be machined with acceptable removal rate and quality by mechanical abrasives, and femtosecond laser (fs-laser) assisted grinding could be a potential method to improve the machinability of SiC. Under fs-laser modulating, SiC surface could be modified to generate laser-induced periodic surface structures (LIPSS). Understanding the mechanical properties and material removal mechanism of the LIPPS surface is crucial to accomplish a high efficiency and quality machining process. This paper aims to investigate the effects of fs-laser modification on the mechanical properties, removal mechanism, removal efficiency, and microstructure changes of 4H-SiC surface during removal, together with those of the original 4H-SiC surface for comparison. The hardness and elastic recovery ability of the modified layer are determined by nano-indentation test, and the nano-scratch test is adopted to study the materials removal behavior. The removal efficiency and the quality of the modified surface is significantly improved. Phase transformation is observed in the scratching area, which reveals the existence of ductile mode removal. Moreover, the stress distribution and the change of scratching force on the surface of SiC before and after modification are studied by finite element method (FEM). The results show that the stress distribution and transmission when scratched on the modified surface is lower than that of the original surface, and the scratching force under the same scratch conditions is greatly reduced. With the understanding of materials removal behavior from the whole process of deformation, phase transformation, and separation of LIPPS from substrate, then the fs-laser modification of SiC could be evidenced as an effective method to improve the grinding efficiency and quality in mass production of industry. [ABSTRACT FROM AUTHOR]