Thorlabs' aspheric lenses, or aspheres, are available molded, CNC-polished, or MRF-polished, either with or without anti-reflection (AR) coatings. Aspheres are often employed to collimate light exiting a fiber or laser diode. The surface of an asphere is designed to eliminate spherical aberration. Compared to their molded aspheric lens counterparts, CNC-polished aspheres are available in larger sizes, provide better surface quality, and maintain the M squared values of the input beam better. MRF-polished aspheres provide true diffraction-limited spot sizes and the lowest wavefront error. We also offer acylindrical lenses, which provide the advantages of aspheres in one-dimensional focusing applications.