As the name suggests, cylindrical lenses are either round or rectangular objects with cylindrically shaped surfaces. They differ from spherical lenses in that they focus a beam to a focal line rather than a focal point.
Transmission is improved by applying an anti-reflection coating on both sides, and multilayer coatings are available for various areas of the light spectrum. Cylindrical lenses can be made from ZnSe, Ge, Si, and other IR materials.
Applications include laser scanners, laser diode systems, spectrophotometers, projectors, and optical data storage and retrieval systems.