First line: 5501a Optics Laser Heads Laser-Interferometer Positioning Systems Choose from large selection optical components system design flexibilityAbstract: .. Compatible with the 10710A Mount. Measurement Plane Mirror Recommendations. Reflectance: 98% at 633 nm at normal incidence. Flatness: Flatness deviations will appear as measurement errors .. Tags: cube beamsplitterbeam Tube"Âoptical Pick-Up headLaser Headinterferometerinterfer*5501a*datasheet abstract..