Plano convex cylindrical lenses are ideal for one-dimensional optical applications. While spherical lenses affect incident light symmetrically in both directions, cylindrical lenses affect incident light only in one direction. Typical applications include using a pair of cylindrical lenses to reshape a distorted beam of light. A pair of planoconvex cylindrical lenses can be used to collimate and circularize the output of a laser diode. Another possible application is using a single cylindrical lens to focus a diverging beam onto a detector array. To minimize spherical aberration, when collimating a beam to form a line, the collimated light should be incident on the curved surface of the lens; and when focusing a line source, the line source should be incident on the flat surface of the lens.