Surface Roughness
Micro-roughness is one of the key parameters affecting mirror performance through scattering. It is also important for diffraction crystals.
Surface micro roughness is measured with the Veeco (Veeco NT2000) non-contacting optical interferometer.
Mirrors are measured on a grid of points over the entire optical area (typically a minimum of 10 points). The system has a resolution of <1Å rms and can measure an area of up to 5x5 mm in one measurement.