Powell prism (Powell Lens) is a specially designed aspheric optical prism, mainly used to convert Gaussian beams (such as laser beams) into linear light spots evenly distributed along a straight line.

This is the Fresnel lens, not one lens really, but numerous tiers of prisms. Lenses like this one turned simple flames into beams upon which sea captains could take their bearings, avoiding risk ...

For several years, Sigma’s lenses have leaned into a sector of image ... It’s designed to deliver both the look of a prism and a special method called second curtain flash as well as stroboscopic.