Three-Dimensional Photoengraving of Monolithic, Multifaceted Metasurfaces

Area of Science:

• Optics and Photonics
• Materials Science
• Nanotechnology

Background:

• Metasurfaces are planar optical elements that manipulate light using sub-wavelength patterns.
• Integrating metasurfaces into 3D structures is challenging but desirable for compact light manipulation.
• Existing methods are limited in creating complex 3D metasurface architectures.

Purpose of the Study:

• To present a novel 3D photoengraving strategy for fabricating composite metasurfaces.
• To demonstrate the integration of diverse sub-wavelength features into 3D monoliths.
• To enable high-throughput, arbitrary inscription and erasing of metasurfaces on 3D structures.

Main Methods:

• Utilized a 3D photoengraving strategy involving multiple interference laser beams.
• Irradiated different facets of an azopolymeric microstructure to generate metasurfaces.
• Employed "photofluidization" for independent inscription and erasing of metasurfaces.
• Fabricated discrete sub-wavelength 1D surface relief gratings on different facets.

Main Results:

• Successfully generated composite metasurfaces on 3D monoliths from a single microstructure.
• Demonstrated independent inscription and erasing of metasurfaces on arbitrary 3D shapes.
• Achieved high-throughput fabrication over areas of approximately a few cm².
• Created a multiplexing structure-color filter using different grating pitches on an inverse pyramidal array.

Conclusions:

• The presented 3D photoengraving technique offers a versatile platform for creating complex 3D metasurfaces.
• This method facilitates the development of advanced 3D optical devices with tailored functionalities.
• The technique enables high-throughput fabrication, paving the way for practical applications in compact optical systems.