Optical pulling force on both right-handed and left-handed chiral particles above a complementary metamaterial

Abstract

Light or electromagnetic waves carry momentum (ℏk) in the direction of their propagation, k. This can develop radiation pressure on any object it faces, enabling the ability to optically manipulate that object. It is normally assumed that a light beam with a photon momentum (ℏk) will always push an object in the forward propagating direction, regardless of its properties. However, in the case of a pulling force, the object is attracted toward the light source when illuminated by a light beam, changing its natural behavior. Optical force on chiral particles has gained much attention in recent literature. Depending on chirality, right-handed and left-handed chiral particles should show opposite behaviors. In this article, we demonstrate an all-optical setup to exert optical pulling force on both right-handed and left-handed chiral particles simultaneously placed above a complementary metamaterial. Simultaneous pulling of oppositely headed chiral particles can significantly enhance optical manipulation efficiency, enable chirality-sensitive detection, and deepen the understanding of light–matter interactions. Our analytical theory suggests that the formation of both electric and magnetic field dipoles inside the chiral particles causes both kinds of chiral particles to experience a pulling force. There is currently no work in the literature that proposes a method to pull both kinds of chiral particles at the same time in an exact setup. Thus, this article offers a unique way to optically manipulate different kinds of chiral materials.