Femtosecond laser shockwave peening ablation in liquids for hierarchical micro/nanostructuring of brittle silicon and its biological application

Abstract

This paper presents a new technique, termed femtosecond laser shock peening ablation in liquids (fs-LSPAL), which can realize simultaneous crack micro/nanomanufacturing and hierarchical micro/nanolaser ablation, giving rise to the formation of diverse multiscale hierarchical structures, such as macroporous ratcheted structures and en échelon microfringes decorated with parabolic nanoripples. Through analysis of surface morphologies, many phenomena have been confirmed to take place during fs-LSPAL, including en échelon cracks, nanostriation, ripple densification, crack branching, and selective formation of high spatial frequency laser-induced periodic surface structures of 100–200 nm in period. At a high laser power of 700 mW, fs-LSPAL at scanning speeds of 0.2 mm s−1 and 1 mm s−1 enables the generation of height-fluctuated and height-homogeneous hierarchical structures, respectively. The height-fluctuated structures can be used to induce ‘colony’ aggregates of embryonic EB3 stem cells. At 200 mW, fs-LSPAL at 1 mm s−1 is capable of producing homogeneous tilt macroporous structures with cracked structures interleaved among them, which are the synergistic effects of bubble-induced light refraction/reflection ablation and cracks. As shown in this paper, the conventional laser ablation technique integrated with its self-driven unconventional cracking under extreme conditions expands the horizons of extreme manufacturing and offers more opportunities for complex surface structuring, which can potentially be used for biological applications.

Diverse nanomaterials synthesized by laser ablation of pure metals in liquids

“…Owing to the invention of the laser system by Maiman [10] in 1960 and its continuous innovation with a milestone of chirped pulse amplification, ultrashort lasers with high powers and short pulse durations and increasingly low prices have become accessible to researchers, which open up many avenues for material processing, such as laser cutting [11], laser functional structuring [12][13][14][15][16], laser machining [17], laser cross-linking [18], 3D/4D laser printing [19][20][21], additive manufacturing [22], and laser patterning [23,24]. Unlike laser additive manufacturing and laser printing techniques that are aimed to construct 3D or 4D structures from smaller-scale building blocks, laser ablation is a subtractive manufacturing technique with micro/nanomaterials as the subtractive materials [11,25].…”

Artificial neural network for cytocompatibility and antibacterial enhancement induced by femtosecond laser micro/nano structures

“…The topological structure modification for implants has been developed greatly in recent years, and lots of studies have been conducted to produce biocompatibility or antibacterial surface on implants [ 14 ]. The implants need to have both good biocompatibility and antibacterial property in clinical applications.…”

Liquid vortexes and flows induced by femtosecond laser ablation in liquid governing formation of circular and crisscross LIPSS

“…Additionally, UPLA/P is capable of surface structuring of a large variety of materials including metals, ceramics, semiconductors, dielectrics, polymers, and two-dimensional materials 17−27 , which involve hard-to-treat materials 26 . Recent UPLA/P innovations have unveiled that new factors such as electric and magnetic fields 28,29 , high-pressure shockwave 30 , and persistent bubbles 18,31 generated during UPLA/P or exerted externally may become new keys to manipulate structure morphologies. Despite the success in generating new types of structures at different scales, it is still challenging to further enrich the structural diversity and unveil the underlying key factors that cause the differences.…”