Object wave retrieval using normalized holograms in three-step generalized phase-shifting digital holography

Area of Science:

• Optical Metrology
• Holography
• Interferometry

Background:

• Phase-shifting interferometry is effective for smooth objects but faces challenges with diffuse surfaces.
• Existing normalization approaches require specific conditions that are difficult to meet for diffuse objects.

Purpose of the Study:

• To propose a generalized three-step phase-shifting method for diffuse objects using a normalization approach.
• To enable accurate complex object wave field retrieval from holograms of diffuse surfaces.

Main Methods:

• A three-step generalized phase-shifting method employing hologram mutual subtraction to suppress zero-order terms.
• Satisfying the norm approximation condition by ensuring phase randomness in holograms.
• An object wave retrieval algorithm that does not require phase-shift value estimation.

Main Results:

• Sufficient suppression of zero-order terms achieved through mutual subtraction.
• Successful estimation of the complex object wave field under the phase randomness condition.
• Validation of the proposed method via simulations and optical experiments.

Conclusions:

• The proposed three-step method effectively extends phase-shifting interferometry to diffuse objects.
• The technique offers a robust solution for complex object wave retrieval without explicit phase-shift calibration.