Introduction: Light manipulation is crucial in making optical technologies smaller. Traditional lenses are limited by thickness, leading to increased demand for flat lenses like metasurfaces. Metasurfaces consist of sub-wavelength structures that modulate light. Fabricating metalenses requires high aspect ratios through specialized techniques. New methods like nanoimprint lithography are being explored to simplify fabrication. Flat lenses are being researched for mass production, with photolithography using steppers being a promising option. The Fresnel zone plate (FZP) is a diffractive optical element with potential for mass production. A study demonstrates the fabrication of visible FZP lenses using a simple process with color resist and stepper technology, achieving impressive results.
https://www.nature.com/articles/s41377-024-01725-6