Controllable optical chirality of vortex beams via photonic jets

Abstract

Recent years have witnessed great interest in the optical chirality of vortex beams carrying orbital angular momentum (OAM). An interesting area of research is the control of such an optical chirality. In this work, we report a study of the controllable optical chirality of vortex beams via photonic jets. Within the framework of the generalized Lorenz–Mie theory (GLMT), we present the analytical expressions for describing the electromagnetic fields of the photonic jets formed on the shadow side of the micro-sized dielectric spheres illuminated by Laguerre–Gaussian (LG) vortex beams. The optical chirality of the vortex beams focused in the near-field area of the photonic jets is numerically simulated. It is revealed that the optical chirality of the vortex beams is drastically enhanced via photonic jets. Moreover, the optical chirality of the vortex beams focused in the near-field area of the photonic jets can be controlled by choosing the radius and refractive index of the dielectric sphere. Such controllable optical chirality is expected to be applicable in chiral manipulation, detection, and recognition.