Picosecond optical vortex pulse illumination forms a monocrystalline silicon needle

Abstract

The formation of a monocrystalline silicon needle by picosecond optical vortex pulse illumination was demonstrated for the first time in this study. The dynamics of this silicon needle formation was further revealed by employing an ultrahigh-speed camera. The melted silicon was collected through picosecond pulse deposition to the dark core of the optical vortex, forming the silicon needle on a submicrosecond time scale. The needle was composed of monocrystalline silicon with the same lattice index (100) as that of the silicon substrate, and had a height of approximately 14 μm and a thickness of approximately 3 μm. Overlaid vortex pulses allowed the needle to be shaped with a height of approximately 40 μm without any changes to the crystalline properties. Such a monocrystalline silicon needle can be applied to devices in many fields, such as core–shell structures for silicon photonics and photovoltaic devices as well as nano- or microelectromechanical systems.

Direct laser printing of chiral plasmonic nanojets by vortex beams

“…As any considerable surface profile evolution of the initially smooth metal film starts after passing the electronphonon relaxation time (few picosecond for noble metal film), helical shape of the nanojets is expected to disappear for pulse durations shorter, than this time. Similar observation was reported for vortex-beam ablation of silicon target [15]. The detailed picture of appearance of such secondary reflected/scattered wave and its interference with the incident one will be a subject of our ongoing experimental studies and theoretical modeling.…”

“…The detailed picture of appearance of such secondary reflected/scattered wave and its interference with the incident one will be a subject of our ongoing experimental studies and theoretical modeling. We believe that this possible alternative explanation of nanojet helicity, together with the present one [15,17], contributes to the basic understanding and supports new elucidating studies of matter structuring by structured light.…”

“…More importantly, vortex laser pulses, carrying simultaneously orbital (OAM) and spin (SAM) angular momenta, were demonstrated to twist transiently molten metal producing chiral-shaped micron-size needles [10,11]. Later, similar effects were used to produce chiral structures on the surface polymers [12][13][14] and semiconductors [15,16]. Based on their experiments with ablation of bulk tantalum targets [17], the authors revealed that mass transfer and handedness of the produced surface structures are associated with corresponding phase helicity (or OAM), while the polarization helicity (or SAM) accelerates/decelerates the movement of the molten material.…”

“…Recently, in a number of papers an alternative pioneering approach, employing optical radiation with specially designed intensity-, polarization-or phase states, was proposed for fabrication of chiral structures [9][10][11][12][13][14][15][16][17][18][19]. In particular, using inherent chirality of nanoparticles, synthesis of twisted nanoribbons through self-assembly in water solution under irradiation with continuous-wave circularly polarized laser radiation was demonstrated * alex.iacp.dvo@mail.ru [9].…”

Stimulated Brillouin scattering phase conjugation of light beams carrying orbit angular momentum (Invited Paper)

“…Vortex beams possess unique phase distribution and orbit angular momentum (OAM) [1] . Therefore, vortex beams have a lot of potential applications in different fields such as optical trapping and manipulation of particles [2] , laser processing [3][4][5] , optical telecommunication [6,7] , and so on.…”