The 81st JSAP Autumn Meeting, 2020

Presentation information

Oral presentation

4 JSAP-OSA Joint Symposia 2020 » 4.3 Lasers and laser materials processing

[11a-Z16-1~9] 4.3 Lasers and laser materials processing

Fri. Sep 11, 2020 9:00 AM - 12:00 PM Z16

Norihiko Nishizawa(Nagoya Univ.)

9:45 AM - 10:00 AM

[11a-Z16-3] Optical vortex induced nano-micro Aluminum structures

〇(DC)Ablez Ablimit1, Ryoga Koike1, Katsuhiko Miyamoto1,2, Takashige Omatsu1,2 (1.Chiba Univ., 2.MCRC)

Keywords:Optical vortex, laser material processing, nano structures

Optical vortex carries a unique ring-shaped spatial intensity and an orbital angular momentum due to its phase singularity, and it has been applied to various fields, such as optical manipulation, quantum communication, and laser materials processing.
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.