Unlike ordinary lenses, cylindrical lens focusses the light onto a line rather than on point due to the spherical radius being in one direction only. Cylindrical lenses are used in different applications like the correction of astigmatism, bar code scanning or laser projection. They are ideal for circularization of diode laser outputs, energy collection for linear detectors or for coupling to a slit input on monochromators or spectrometers. Another typical application of a is in the light sheet microscope where a cylindrical lens is placed in front of the illumination objective to create the light sheet used for imaging.