Generating Helical Polymorphic Beams Using Dielectric Metasurfaces

Abstract

Helix-shaped polymorphic beams are structured optical fields formed by the coherent superposition of Bessel beams with carefully selected orders. Their intensity maxima trace a helical trajectory during propagation. By engineering the transverse phase and amplitude, these beams generate optical forces for particle propulsion and trapping. Upon interaction with particles, the resulting axial forces can be either attractive or repulsive, enabling operation in tractor-beam or pushing-beam regimes. Their generation has traditionally relied on bulky and expensive spatial light modulators, whereas metasurfaces provide a compact and cost-effective alternative. While metasurfaces have been used to g..