Flat Lenses

Smooth interfaces between two media are typically used to shape wavefronts in optical design. Spherical and aspherical interfaces are utilized in the creation of lenses and mirrors in imaging systems. In nonimaging optics, freeform surfaces are employed to deliberately introduce particular aberrations to shape the energy distribution of light. In every scenario, the surface performs a transformation of the incoming wavefront’s phase into a specific output phase that aligns with the design criteria.

Flat surfaces can be utilized to achieve the same phase transformations that are typically conducted with smooth surfaces. This paper explores the fundamental principles involved in designing flat lenses, including Fresnel lenses, diffractive lenses, and metalenses.

This paper derives from the transcript and slides of the webinar "Flat Lenses: Tracing the Evolution from Smooth Surfaces to Fresnel, Diffractive, and Metalenses," presented by Frank Wyrowski at the Photonics Media webinar on May 22, 2024.