Spatio‐Spectral Customized Light Structures for Subwavelength Highly Resolved Multiplexing of Diffractive Optics

Abstract Standing‐waves created by counter‐propagating light beams can adopt various forms, offering flexible and efficient methods for recording complex periodic structures in polarization‐sensitive materials. Compared to conventional holographic/lithographic techniques, this approach simplifies the encoding of intricate and customizable light structures with finely tunable periodicities and highresolution. It also overcomes limitations at submicrometric periodicities, where traditional methods struggle to maintain fidelity to desired designs. This study explores 1D standing‐waves with different polarization gradients, such as corkscrew and Sisyphus patterns. Generated by laser beams operating in multiline‐mode with decoupled intensity and polarization control, these light structures can encode multiple, independent polarization volume gratings simultaneously in a single‐step process. Submicrometric periodicities are achieved by positioning the material layer at a tilting angle within the standing‐wave, allowing fine‐tuning of the recording periodicities with a few nanometers spatial resolution. The resulting gratings diffract light at notably large angles, preserving polarization properties and avoiding crosstalk. These spatio‐spectral structures hold transformative potential for ultra‐compact optical systems. Key applications include material structuring, advanced information processing with higher capacity and security, and augmented/virtual reality platforms, where efficient polarization control ensures high‐fidelity image projection and interaction. This method opens unexplored opportunities for scalable, high‐resolution applications in cutting‐edge optical technologies.