Micro Ball Lens 1mm Worldhawk can provide a variety of optical ball lenses, including micro ball lens for optical fiber coupler or semiconductor laser, IR ball lens, UV ball lenses and crystal ball lenses such as ge, Si and Zns...   Ball Lens Cap  Ball Lens Cap consists of a high-precision Micro Ball sealed in a can cap made of sealing alloy with glass frit. You can choose the standard type for TO-56 and TO-46, depending on the desired application.  Parameter: Item    Parameter (Optical glass ball lens; Half ball lens)   Material   K9 (BK7), Optical sapphire(ruby) glass, Fused Silica, JGS1,   ZnSe,  Zns, Ge, Caf2, B270, LaF52, Schott glass   Diameter   1~150mm, 1mm, 2mm, 3mm…   Dia. Tolerance   +/-0.002mm   Roundness   0.003-0.005   Surface Accuracy   <2λ   Irregularity   λ/2 @632.8nm   Surface Quality   <40/20 scratch/dig   Clear Aperture   >92%   Focal length tolerance   +/-1% (+/-5% for 400 series)   Centration   3 arc min or better   Coating   Upon customer request Materail Specification Glass  Materials Refractive  (nd)   Dispersion  Coefficient(vd)  Glass  Materials Refractive  (nd)   Dispersion  Coefficient(vd)   H-Zlaf90   2.00069   25.43   Sapphire   1.768   72.20   H-Zlaf50D   1.804   46.58   ZnSe   2.403   N/A   H-ZF7LA   1.80518   25.46   Silicon   3.422   N/A   Fused Silica   1.458   67.70   Germanium   4.003   N/A   H-K9L(N-BK7)   1.517   64.20