Absolute testing of the reference surface of a Fizeau interferometer through even/odd decompositions.

Area of Science:

• Optical Engineering
• Metrology

Background:

• Absolute testing of spherical surfaces is critical due to rising accuracy demands.
• In Fizeau interferometry, reference surface errors significantly impact measurements.

Purpose of the Study:

• To demonstrate the validity of a previously proposed absolute testing procedure for reference surfaces.
• To address the challenge of accurate spherical surface metrology.

Main Methods:

• The procedure decomposes surface deviations into odd and even components.
• Odd deviations are measured using a basic and a 180-degree rotated auxiliary sphere.
• Even deviations are determined via a cat's eye double-pass configuration with a half-screen aperture.

Main Results:

• The study confirms the effectiveness of the absolute testing method for reference surfaces.
• The decomposition technique allows for accurate separation of surface error contributions.
• The method is compatible with partially coherent illumination.

Conclusions:

• The validated absolute testing procedure provides a reliable method for characterizing spherical reference surfaces.
• This technique enhances the accuracy of Fizeau interferometry.
• It is applicable in various metrology contexts requiring high precision.