Microneedle structuring of Si(111) by irradiation with picosecond optical vortex pulses

Abstract

We report on comparative studies of the optical vortex-induced structures of both Si(100) and Si(111) by irradiation with a single optical vortex picosecond pulse. Furthermore, we address the effects of the total angular momentum (TAM) on the optical vortex-induced microneedle. Si(111) allows for the faster growth of the microneedle, although this impacts the monocrystallization of the needle. The TAM then forces the melted silicon to spin axially, thereby yielding an efficient accumulation of melted silicon on the substrate for microneedle formation. These results provide new fundamental insights into the interactions between optical vortex fields and irradiated materials.