Polarization-Controlled Broadband Accelerating Beams Generation by Single Catenary-Shaped Metasurface

Self-accelerating beams have drawn enormous attentions in optics owing to their nondiffracting and self-healing properties. Traditionally, the generation of such beams demands bulky devices and a long working distance, which impede the miniaturization of the optical system. Recent progresses in metasurfaces facilitate replacing cumbersome optical components by ultrathin and planar nano-optical devices. Nevertheless, most of the existing approaches suffer from fixed trajectories, narrow operation bandwidth and low efficiency. Here, a methodology is proposed to generate self-accelerating beams with arbitrary profiles by employing a generalized analysis based on geometric optics and interference theory. As a proof of the concept, single catenary-shaped metasurface is utilized to generate the cubic phase shift, which leads to a reciprocal accelerating trajectory. The spatially continuous and spectrally dispersionless catenary nanoapertures show great advantages in terms of bandwidth and efficiency over discrete counterparts. The polarization-controlled accelerating trajectories are demonstrated by both simulations and measured results. The proposed compact and efficient beam generators are believed to be promising for future on-chip and integration applications.