Cylindrical lenses with negative focal length expand beam along one coordinate. Typical application for the lenses is beam shaping. Round laser beam can be focused into a line-spot with help of the lens. Anamorphic shape of the image/beam can be realized by using pair of cylindrical lenses, which makes it irreplaceable tool for circularization of diode laser output beams.
Yutai Optics can customize rectangular or round shape, coated or not negative cylindrical lenses.