Chirality of optical vortex beams reflected from an air-chiral medium interface.

Chirality plays an important role in understanding of the chiral light-matter interaction. In this work, we study theoretically and numerically the chirality of optical vortex beams reflected from an air-chiral medium interface. A theoretical model that takes into full account the vectorial nature of electromagnetic fields is developed to describe the reflection of optical vortex beams at an interface between air and a chiral medium. Some numerical simulations are performed and discussed. The results show that the chirality of the reflected vortex beams can be well controlled by the relative chiral parameter of the medium and is significantly affected by the incidence angle, topological charge, and polarization state of the incident beam. Our results provide new, to the best of our knowledge, insights into the interactions between optical vortex beams with chiral matter, and may have potential application in optical chirality manipulation.

Light scattering of Laguerre-Gaussian vortex beams by arbitrarily shaped chiral particles.

Laguerre-Gaussian (LG) beams with vortex phase possess a handedness, which would produce chiroptical interactions with chiral matter and may be used to probe structural chirality of matter. In this paper, we numerically investigate the light scattering of LG vortex beams by chiral particles. Using the vector potential method, the electric and magnetic field components of the incident LG vortex beams are derived. The method of moments (MoM) based on surface integral equations (SIEs) is applied to solve the scattering problems involving arbitrarily shaped chiral particles. The numerical results for the differential scattering cross sections (DSCSs) of several selected chiral particles illuminated by LG vortex beams are presented and analyzed. In particular, we show how the DSCSs depend on the chiral parameter of the particles and on the parameters describing the incident LG vortex beams, including the topological charge, the state of circular polarization, and the beam waist. This research may provide useful insights into the interaction of vortex beams with chiral particles and its further applications.