When illuminated sideways, these cut-rods act as cylindrical lenses whose NA is proportional to their diameter and their refractive index. They can be used in the visible and near infrared spectrum.
These lenses are suitable either as slow-axis collimators (SAC lens) for single laser diodes or for building cylindrical lens arrays for laser diode bars. In order to accommodate a small emitter pitch, the edge of the lens may be ground to a desired width.
Cut-rod lenses are made from glass rod lenses that are cut and ground to desired length and width.