Varifocal Alvarez metalens array for adaptive light-field imaging

Area of Science:

• Optics and Photonics
• Metasurfaces
• Computational Imaging

Background:

• Metalens arrays offer compact solutions for light-field imaging.
• Fixed focal lengths of traditional metalenses limit adaptability and depth-of-field control.
• Achieving dynamic focusing in compact imaging systems remains a challenge.

Purpose of the Study:

• To demonstrate adaptive light-field imaging using a varifocal Alvarez metalens array.
• To enable dynamic focusing and expand the depth range of plenoptic imaging systems.
• To develop a method for reconstructing high-resolution, all-in-focus images from multi-focus captures.

Main Methods:

• Fabrication of a varifocal Alvarez metalens array composed of two bonded metasurfaces with cubic-phase sub-regions.
• Achieving continuous focal length tuning via relative lateral displacement of the metasurfaces.
• Integration into a plenoptic imaging system and application of a MultiLensFusion algorithm for image reconstruction.

Main Results:

• Demonstrated continuous focal length tuning from 3.33 mm to 4.50 mm.
• Enabled dynamic focusing and expanded depth range in a light-field imaging system.
• Successfully reconstructed high-resolution, all-in-focus images using the MultiLensFusion algorithm.

Conclusions:

• The varifocal Alvarez metalens array provides a compact and versatile platform for adaptive light-field imaging.
• This technology overcomes the limitations of fixed focal lengths in metalens-based systems.
• Offers a pathway for next-generation imaging systems with tunable optical responses.