Broadband Efficient Dual-Polarization Airy Beam Generation with Reflective Metasurface

This study demonstrates that continuous amplitude and binary phase modulation suitable for Airy beam encoding can be frequency-independently obtained with not only cross-polarized but also copolarized transmitted/reflected electromagnetic field components by rotation of unit cell with reflection symmetry. Maximum device efficiency can be achieved with relevant Airy beam generator, when the eigen polarization states of the unit cell are two orthogonal linear polarization states, and the copolarization reflections of them are out of phase and both have the amplitude of unity. As a proof of principle, broadband and high-efficiency reflective Airy beam generators based on both copolarization and cross-polarization modulation approaches are fabricated with cut-wire structure as unit cell. The measured results show that the efficiency of the devices is approaching the theoretical limit in a wide frequency range.