Laser nano- and micro-structuring of silicon using a laser-induced plasma for beam conditioning

A technique based on the interaction between a laser pulse and a laser-induced plasma is proposed as a very simple and potentially powerful method for surface nanostructuring. A laser pulse was focused onto a metallic target in order to generate a plasma, while a second laser pulse was directed to the plasma and crossed it perpendicularly to the first pulse and, subsequently, hit a silicon substrate. In this conditions, the second pulse interacts with the plasma which acted as an optical element whose properties could be modified by varying the energy density of the first pulse or the delay between the two pulses. Microscopic analysis carried out on the silicon surface revealed a wide variety of nanostructured patterns.