Conical microspike morphology formation and control on various metal surfaces using femtosecond laser pulse

초록

Formation of conical microspikes on various metal surfaces (316L stainless steel, Ti-6Al-4V, and Al5754) under femtosecond irradiation at high repetition rate is reported. Two types of microcone morphologies formed at these high repetition rates under high and low-fluence conditions were clearly distinguished. At low fluence (near the ablation thresholds), conical spikes with high aspect ratio and nonuniform distribution forms through random evolution. At high fluence, semiuniform conical spikes are formed through a simultaneous progressive evolution procedure with increasing the number of scans. Experimental results are presented showing the progression of random microspike formation to uniform microspikes as fluence increases and show how scan-speed affects the size of the spikes. Also, extraordinary absorption coefficient is measured for nonuniform conical spike covered 316L stainless steel formed under near threshold condition. (C) 2016 Laser Institute of America.

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