Patent ID: 11892283
Assignee: CARL ZEISS SMT GMBH
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 10:
11. A method for interferometrically determining a shape of a surface of a test object, comprising:
providing a multiply-encoded diffractive optical element, which is configured to produce by diffraction from an input wave a test wave, which is directed at the test object and has a wavefront formed as a free-form surface, as well as at least one calibration wave,
calibrating the diffractive optical element as claimed in claim 9,
capturing a measurement interferogram produced by the reference wave with the test wave after interacting with the surface of the test object, and
ascertaining the shape of the surface of the test object by evaluating the measurement interferogram, in accordance with the calibration interferogram.