Phys.org May 16, 2024
A new generation of diffractive components integrating specific geometry with additional features (flexibility, stretchability, rotation, and other approaches for tuning properties) extends the functionality of wavefront control. Researchers in Russia demonstrated an innovative approach to control the THz wavefront via a layered composition of spiral zone plates (SZPs) with tunable mutual orientation and scaling. As a proof of concept, they designed the SZP with experimental characterization of the resultant vortex beams. For each single SZP, a flexible element was proposed based on thin film of single-walled carbon nanotubes deposited on a stretchable substrate. The diffraction element could be tuned not only by rotation (along the azimuthal direction), but also by its stretching (in the radial direction). According to the researchers spatial tuning of SZPs they developed opens an efficient, convenient, and highly customizable approach for the manipulation of vortex beams… read more. TECHNICAL ARTICLE
Spiral zone plate fabrication process. Credit: Arina Radivon et al