Large‐Scale Multiplexed Azopolymer Gratings with Engineered Diffraction Behavior. Issue 21 (11th October 2021)

• Record Type: Journal Article
• Authors: Oscurato, Stefano L.; Reda, Francesco; Salvatore, Marcella; Borbone, Fabio; Maddalena, Pasqualino; Ambrosio, Antonio
• Is Part Of: Advanced materials interfaces. Volume 8:Issue 21(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-10-11
• Subjects: azopolymers -- diffraction gratings -- interference lithography -- mass migration -- polychromatic diffraction -- reconfigurable diffractive optical elements -- RGB gratings; Materials science -- Periodicals; 620.11
• DOI: 10.1002/admi.202101375
• Languages: English
• ISSNs: 2196-7350

Abstract

Abstract: The diffraction of polychromatic light from periodic superficial structures is often responsible for the structural colors observed in Nature. Similarly, engineered microtextures fabricated on metallic or dielectric surfaces can be used to design diffracted optical patterns with desired shapes and colors. To this aim, advanced diffraction gratings with exceptional design and functionality are continuously proposed, and new fabrication methods follow to stay abreast with the improving design capabilities. Multiplexed surface reliefs, acting as complex gratings with tunable diffraction behavior, can be readily produced on films of azobenzene containing materials by exposing the surface to controlled sequences of holographic interference patterns. This work fully investigates, both theoretically and experimentally, the use of light‐induced surface relief on azopolymers for the realization of large‐scale multiplexed gratings with optimized diffraction performances. The reconfigurable diffraction gratings able to diffract polychromatic light in the same direction with controllable relative color intensities by tuning exposure parameters in a switchable two‐beam interference setup are designed and fabricated. The results can be generalized to more complex diffractive devices, usable in emerging display application areas. Abstract : Sequential exposures of an azopolymer to switchable interferograms produce large‐scale multiplexed relief gratings directly on the film surface. These gratings engineer the shape and the chromatic behavior of the emerging diffraction pattern. Here, an optimized multiplexed azopolymer diffraction grating that redirects polychromatic light in the same diffraction order is fully characterized by theoretical design and highly accurate experimental realization.