Regulation and characterization of photonic hook of eccentric ellipsoidal particles

Abstract

Photonic hook (PH) is a new type of curved subwavelength light beam generated at the shadow side of asymmetrical particles, which has aroused widespread interest since its numerical simulation implementation and experimental confirmation. However, the generation of PH is strongly dependent on particles with complex structures that are difficult to process and there is no comprehensive evaluation criterion for the properties of PH. In this work, a simple bilayer eccentric microelliptic column which is easy to process is proposed, and the length and bending angle of the PH can be tuned by varying the eccentricity, the refractive index of material, the ellipsoidal deflection ratio, and the angle of incident of light. In addition to a single property of PH, such as bending angle or effective length, its integrated performance has been fully analyzed for the first time with the aid of a quality factor QPH. And QPH can be used as a parameter to measure the comprehensive properties of PH. Meanwhile, high-quality PH can be attained by referring QPH with curved angle up to 34°and effective length up to 16.5 λ, as well as PH with the value of QPH up to 108. The obtained results can be used to synthetically evaluate the properties of PH, and they are conducive to achieving tunable PH with simple structures in future research.