Plano-concave cylindrical lenses and negative cylindrical lenses function similarly to plano-concave spherical lenses, but operate only along a single axis. These cylindrical lenses are used in applications requiring one-dimensional shaping of a point source. A typical application is converting a collimated laser beam into a line beam using a single cylindrical lens. A pair of cylindrical lenses can be used to shape an image. To minimize spherical aberration, the curved surface of the lens should be oriented toward the source when diverging the beam.