The LT Ultra metal optics are ground to nanometer (one-millionth of a millimeter) accuracy – which is important so that as little laser light as possible is lost due to light scattering and diffraction on the diamond-machined mirror surface. The crystalline structure of the metal itself defines the flatness limit.

For non-contact measurement testing of both form (PV values) and surface finish (Ra values), LT Ultra uses its own interferometers during production and final inspection stages. These devices are calibrated regularly in line with prevailing international standards.