Interferometric system having a reference surface including a mirrored zone

A method for operating an interferometric system, the interferometric system including an illumination arm, having a light source and an illuminating optical system to form an illuminating beam path, an object arm having a reference element to measure an object to form an image-ray path, the object to be measured having an object surface inaccessible to direct illumination, a reference arm, a detector arm having a detector, and a beam, the method comprising:

• bringing light beams reflected by an object surface accessible to direct illumination to interference with light beams reflected by a reference surface, while light beams reflected by the object surface inaccessible to direct illumination are reflected via a mirrored zone and then brought to interference with light beams reflected by an associated reference surface.

A method for operating an interferometric system for measuring an object, the interferometric system including an illumination arm having a light source and an illuminating optical system to form an illuminating beam path, an object arm, having a reference element, to form an image-ray path, the object to be measured having an object surface inaccessible to direct illumination, a reference arm, a detector arm having a detector, and a beam splitter, the method comprising:

• bringing light beams reflected by an object surface inaccessible to direct illumination that are additionally reflected via at least one mirrored zone to interference with light beams reflected by an associated first reference surface, while light beams reflected by a second object surface are brought to interference with light beams reflected by an associated second reference surface, the associated first reference surface, the associated second reference surface, and the at least one mirrored zone being provided in the reference element situated in the object arm.