9:45 AM - 10:00 AM
▲ [11a-Z16-3] Optical vortex induced nano-micro Aluminum structures
Keywords:Optical vortex, laser material processing, nano structures
In this presentation, we report on a nano - micro needle structuring of aluminum (Al) by the illumination of picosecond optical vortex pulses. A single optical vortex pulse with a wavelength of 1064 nm, a pulse width of ~20 ps, and pulse energy of <25 mJ was focused to be an annular spot with a diameter of ~20 mm on an Al substrate, and it twisted the irradiated Al to shape a helical nanoscale needle with a tip curvature of ~200 nm (i.e. helical nanoneedle) owing to the orbital angular momentum (OAM) transfer effects. This helical nanoneedle was transformed into a non-helical microneedle by deposition of 4 overlaid optical vortex pulses, and its height reached up to ~7 mm.
Such dual-scale Al surface structuring provides a novel physical insight for interaction between OAM and materials, and it also offers an entirely new nano/microfabrication technique towards ultraviolet plasmonic devices.