Chiral nanoparticles in singular light fields

Abstract

The studying of how twisted light interacts with chiral matter on the nanoscale is paramount for tackling the challenging task of optomechanical separation of nanoparticle enantiomers, whose solution can revolutionize the entire pharmaceutical industry. Here we calculate optical forces and torques exerted on chiral nanoparticles by Laguerre–Gaussian beams carrying a topological charge. We show that regardless of the beam polarization, the nanoparticles are exposed to both chiral and achiral forces with nonzero reactive and dissipative components. Longitudinally polarized beams are found to produce chirality densities that can be 109 times higher than those of transversely polarized beams and that are comparable to the chirality densities of beams polarized circularly. Our results and analytical expressions prove useful in designing new strategies for mechanical separation of chiral nanoobjects with the help of highly focussed beams.

Optical trapping with structured light: a review

“…[249][250][251][252][253] There is no doubt that new developments in structured light beams will continuously boost the fields of optical manipulation. 254 Moreover, among the diverse optical trapping schemes discussed in this review, in our view, several topics have great potential to find exciting future applications, such as the optical trapping of metal particles [183][184][185][186][187][188][189] and chiral particles, 52,53 vacuum levitation, structured light in waveguides, [255][256][257][258][259] optical binding and other collective motions in structured light fields, 113,185,[260][261][262] quantum optomechanics, 30 and optical trapping for multidisciplinary applications. 32 In the future, besides SLMs and DMDs, more flexible, efficient and much less expensive devices will be developed to produce structured beams, which can help build the next generation of optical trapping technology.…”

“…40 Crucially, in recent time, it was demonstrated that SAM can also be used for the selective 3D trapping of chiral micro-and nanoparticles. 52,53 It was shown that under appropriate conditions, a light beam with SAM can induce nonrestoring or restoring forces on chiral microparticles. 52 Similar results have been also reported on the interaction of chiral nanoparticles with chiral optical fields.…”

“…52 Similar results have been also reported on the interaction of chiral nanoparticles with chiral optical fields. 53 In 1992, Allen et al 25 introduced the concept of a light beam possessing OAM, which is in addition to any SAM and characterized by an azimuthally varying phase of expðilφÞ, where l is an integer value, termed the topological charge, and φ is the azimuthal angle. The first experimental demonstration of OAM transfer from light to matter, in the context of optical tweezers, was performed by the group of Rubinsztein-Dunlop, 54,55 who demonstrated the optically induced rotation of absorptive particles.…”

Optical Enantioseparation of Racemic Emulsions of Chiral Microparticles

“…By doing so, this work opens the way for further experimental implementation by considering particles with smaller sizes, toward the grail of all-optical resolution of chiral entities at the nanoscale. Finally, we note recent theoretical discussions on the possible use of a chiral light field endowed with chiral features that are not associated with the polarization state, as is the case for light fields carrying optical-phase singularities [44], which is another option through which to explore the experimental feasibility of alternative chiral optomechanics approaches.…”

Nanoparticle-based Chemiluminescence for Chiral Discrimination of Thiol-Containing Amino Acids

“…However, these methods cannot make an effective discrimination between D- and L- enantiomers. On the other hand, various analytical techniques, including high-performance liquid chromatography (HPLC), thin-layer chromatography (TLC), capillary electrophoresis (CE), gas chromatography, mass spectrometry 25 – 36 , circular dichroism (CD) 37 , fluorometry 38 , nuclear magnetic resonance (NMR) protocols 39 , 40 and using chiral light fields 41 – 44 have been reported to distinguish the chirality of PA, Cys, and other chiral compounds. However, most of these techniques have several drawbacks such as laborious setup process, expensive chiral columns, complicated sample pretreatment, complex operation process and high-cost chiral stationary phases or chiral selectors.…”