Precise phase retrieval under harsh conditions by constructing new connected interferograms.

Area of Science:

• Optical metrology
• Interferometry
• Phase retrieval

Background:

• Accurate phase map retrieval from limited, noisy interferograms with low phase shifts remains a challenge.
• Existing phase-shifting methods struggle under harsh conditions, leading to significant errors.

Purpose of the Study:

• To develop a novel phase retrieval method overcoming limitations of existing techniques under harsh conditions.
• To improve accuracy and robustness in phase map reconstruction from noisy interferometric data.

Main Methods:

• Constructing a set of connected interferograms using simple addition and subtraction operations.
• Ensuring a consistent phase-shift interval of π/2 across all subset interferograms.
• Processing the connected interferograms with conventional methods like Principal Component Analysis (PCA) or Average Intensity Average (AIA).

Main Results:

• Achieved significant reduction in Root Mean Square (RMS) errors: up to 93.7% compared to PCA and 89.3% compared to AIA.
• Demonstrated high precision and robustness against noise in phase retrieval.
• Validated the method's effectiveness through both simulations and experimental results.

Conclusions:

• The proposed novel method effectively retrieves phase maps from a small set of noisy interferograms with low phase shifts.
• Offers a precise and robust solution for phase retrieval under challenging conditions.
• Outperforms conventional PCA and AIA methods in terms of error reduction and reliability.