Generation of vector elliptical perfect optical vortices with mixed modes in free space

Experimental realization of a transmissive microwave metasurface for dual vector vortex beams generation

This work presents a theoretical design and experimental demonstration of a transmissive microwave metasurface for generating dual-vector vortex beams (VVBs). The proposed metasurface consists of an array of pixelated dartboard discretization meta-atoms. By rotating the meta-atoms from 0° to 180°, a Pancharatnam-Barry (P-B) phase covering the full 360° range is achieved, with a transmittance exceeding 90% over the frequency range from 9.7 to 10.2 GHz. The measured results demonstrate that when a linearly polarized microwave normally impinges on the metasurface, the transmitted beams correspond to the dual VVBs with different directions. A good agreement among Poincaré sphere theory, full-wave simulation, and experimental measurement is observed. This proposed transmissive microwave metasurface for VVBs may offer promising applications in communications and radar detection.

Arbitrary combinations of helical-conical optical beams in free space

Helical-conical optical beams (HCOBs) have attracted considerable interest due to their peculiar optical features. Their characteristic helical light intensity distribution has exerted unprecedented advantages in many fields, but multiple combinations of HCOBs have not been reported due to the limitations of algorithms and light field modulation techniques. We propose and experimentally demonstrate arbitrary combinations of multiple HCOBs in free space to construct hybrid HCOB arrays. The similarity between the experimental results and the numerical simulation results is 94.22%. The initial orientation of the HCOBs is flexibly tuned by the rotation factor β, and the optical pen is used to combine the HCOBs. This approach allows multiple parameters in the array to be precisely tuned, including the type, number, and position of HCOBs, adding more design flexibility. The constructed HCOB arrays have a higher degree of modulation freedom and may find applications in fields where dynamic control is in high demand, including optical tweezers, biological cell sorting, and multiparticle manipulation.