Ball lenses are highly polished spheres made of optically transparent homogeneous materials. A carefully controlled manufacturing process produces spheres with precise diameters and unsurpassed surface quality. Ball lenses are commonly used for laser collimating and focusing, laser-to-fiber coupling, fiber-to-fiber coupling, and fiber-to-detector coupling. Larger spheres are easier to handle and ease the sensitivity of translational alignment. Half-ball (hemispherical) lenses are ideal for applications such as fiber communications, endoscopy, microscopy, optical pickup devices, and laser measurement systems.