Twisted Rainbow Light and Nature‐Inspired Generation of Vector Vortex Beams

Abstract

Twisted vector light beams (optical vortices) arise from a spiral modulation of the geometric (Pancharatnam–Berry) phase converting the light spin to the orbital angular momentum. The preferred geometric‐phase elements using liquid crystals and plasmonic metasurfaces realize this conversion by structuring their building blocks, i.e., precisely orienting individual crystal molecules or plasmonic nanoantennas. Here, an analogous mechanism is discovered in the spiral phase modulation of light reflected by dielectric spheres and first demonstrated in natural phenomena, namely in the rainbow formation. The spiral geometric phase is documented by holographic imaging of full circle primary and secondary rainbows created in the laboratory. The measurement uses a wide‐angle holographic camera (field of view ≈120°) taking time‐resolved self‐correlation holograms (300 ms). The holograms allow a quantitative restoration of the spiral geometric phase of light reflected from thousands of randomly falling water drops. The capability of individual drops to generate vector vortex beams under circularly polarized illumination is proven theoretically and demonstrated in experiments using glass microspheres. The spherical reflectors are discovered as simple generators of vector vortex beams and vortex arrays, inspiring novel geometric‐phase elements.

Ultrabroadband Multichannel Vector Vortex Beams With Versatile Electrically Induced Functionality

“…Vector vortex beam (VVB), together with the two subcases as vector beam and vortex beam, are known as typical structured light with optical singularities. [1][2][3][4] To be specific, vector beams intrinsically hold the polarization singularities originating from the inhomogeneous polarization in the spatial domain, which have been widely adopted in many areas such as optical manipulation, [5] superresolution microscopy [6] and robust light DOI: 10.1002/lpor.202300098 propagation. [7] On the other hand, vortex beams with phase singularities are characterized by the helical phase front and the carried orbital angular momentum (OAM), promising in many areas such as optical tweezers, [5] information processing, [8] optical multiplexing, [9] and quantum systems.…”

Dynamic Control of Hybrid Grafted Perfect Vector Vortex Beams

“…Benefiting from the unprecedented manipulation of phase, amplitude, and polarization 14,15,16,17 , optical metasurfaces have provided a compact platform to realize various vortex beams such as perfect vortex beams 11,18 , ring vortex beams 19,20,21 , OAM holography 22,23,24 , vector beams 25,26,27,28 , and vector vortex beam (VVBs) 25,26,27,28 . Recently, we experimentally demonstrated a compact platform to generate and manipulate GVBs 29 .…”