Testing the trueness of circular surfaces: a simple holographic method

Area of Science:

• Optical Metrology
• Holographic Interferometry
• Precision Measurement

Background:

• Conventional holographic interferometry faces limitations with object surface properties and decorrelation.
• Accurate measurement of object motion and surface variations is crucial in various scientific and engineering fields.

Purpose of the Study:

• To introduce and validate a new holographic method that transfers object motion or variation to a probe.
• To demonstrate the advantages of this novel technique over traditional holographic interferometry.

Main Methods:

• Theoretical development of the holographic probe transfer method.
• Experimental verification using an Ealing precision self-centering lens holder as the probe.
• Analysis of the method's sensitivity, decorrelation resistance, and applicability to various object surfaces.

Main Results:

• The method successfully transfers object variations to the probe, enabling measurement.
• Four discrete sensitivities were achieved, allowing measurement of radius changes from one to a few hundred wavelengths.
• The technique avoids decorrelation problems, enabling comparison of different surfaces and removing limitations on object light scattering or transmission.

Conclusions:

• The proposed holographic probe transfer method offers significant advantages over conventional holographic interferometry.
• It provides enhanced flexibility and accuracy for measuring object motion and surface variations.
• The method's limitations were also discussed, indicating areas for future research.