Ball lenses belong to a special form of biconvex lenses which have the geometry of a ball(sphere). They are manufactured from a single material, usually an optical glass with good transparency in the wavelength region of interest. The typical applications of ball lenses include focusing light in the field of fibers(e.g. laser to fiber coupling ,fiber to fiber coupling), emitters and detectors.Half-Ball lenses are variants of ball lenses, they are ideal for for more compact designs.