Fresnel lenses, however, don’t require curvature of any kind, but instead utilize concentric flat rings to diffract light, with the rings’ size and width determining the overall lens focal length.

Unlike a traditional dome-shaped lens, a Fresnel lens uses precisely angled concentric grooves on the surface of a clear flat panel to focus light on a specific point. This lets Fresnel lenses ...

The most important part of a lighthouse might be one of the beautiful tools hidden inside of it: the Fresnel lens, a breakthrough that changed seafaring and saved lives. As the above video shows ...