Hybrid metamaterials combining zero-index and graded-index materials for multi-directional Bessel beam generation

Abstract

Bessel beams, characterized by their unique non-diffractive and self-healing properties, have been a focal point in optical research. They offer unique advantages in various applications, from high-resolution imaging to the enhancement of optical communication. However, traditional methods of Bessel beam generation face limitations in producing multiple beams simultaneously, which hinders the application of complex light manipulation and multiple beam pathways. In this work, by merging the wave steering function of zero-refractive index metamaterials and the phase tailoring functionality of dielectric metasurfaces, we have realized the generation of multi-directional Bessel beams with the hybrid metamaterials. The multidirectional Bessel beams are not only self-healing to the defects along the propagation paths but also robust to the defects in the Bessel beam generator. Notably, the intrinsic zero-index property facilitates the minimization of light crosstalk beyond the hybrid metamaterials, preventing interference and providing a disturbance-free environment for the generation of Bessel beams. Our results provide a new perspective on designing novel optical devices with multi-channel and open novel routes to steer the electromagnetic waves in nano-scale structures.