Plano-concave cylindrical lens, also known as negative cylindrical lens, is composed of one plane and one concave cylinder, and its focal length is negative. It is often used to focus parallel or divergent beams on the line or change the width to height ratio of the image. Planar concave cylindrical mirrors can be realized by plating reflective films.

These cylindrical lenses are used for applications that require shaping point light sources in one dimension. A typical application is to convert a collimated laser beam into a linear beam using a single cylindrical lens. A pair of cylindrical lenses can be used to shape the image. To minimize spherical aberration, the surface of the lens should be directed towards the light source when the beam is diverged.