Comes with a double-pass method He-Ne laser interferometer length measuring system made by our company equipped on a surface type XYZ stage set upon a stone plate furnished with an active vibration isolation stage. Laser wavelengths are corrected through optics tracking and stage positioning is restrained to a resolution of 0.3nm through use of a plane mirror. There is also a full complement of software correction functions such as curvature correction and grid/line width correction.