N-BK7 plano-convex lenses are polished to great tolerance with master test plates to ensure minimum wave front distortion for demanding electro-optic focusing purpose. N-BK7 is a great lens material for most visible applications. N-BK7 is the most common crown optical material, it provides good performance at a good value. Our single layer Magnesium fluoride AR coating is a common coating that offers an extremely broad visible wavelength range at a reasonable price. Compared to the uncoated surface, the MgF2 coating provides a significant improvement by reducing the reflectance to less than 1.5%. Broadband multilayer AR coating is also available, 350-650nm, 400-700nm and 650-1050nm.
Our Custom made specifications:
| Diameter range | 2mm to 800mm |
| Tolerance | +/-0.05mm |
| Thickness tolerance | +/-0.05mm |
| Surface quality | 20/10 or 40/20 |
| Surface accuracy | L/4 or better |
| Centering | 1 arc mins |
| Bevel | Protective bevel |
| Coating | Single layer AR coating or broad band AR coating for different wavelengths, R<0.5% or better |
| Substrate | N-BK7 or H-K9L finely |
