Spectrally resolved interferometry based on a tilt phase-shifting iteration method

Area of Science:

• Optical Metrology
• Interferometry
• Signal Processing

Background:

• Phase extraction from spectral interferograms faces challenges due to uneven phase shifts.
• Existing methods struggle with random phase shifts and high-noise environments.

Purpose of the Study:

• To develop a novel method for accurate phase extraction in spectrally resolved interferometry (SRI).
• To overcome limitations of traditional phase-shifting techniques in spectral interferometry.

Main Methods:

• A tilt phase-shifting iterative method is proposed, integrating spectral interferogram reconstruction.
• The method reconstructs spectral interferograms to create a linear tilt in phase shifts.
• Phase extraction is performed using at least three frames with random phase shifts.

Main Results:

• The novel method achieves high-quality phase extraction, overcoming limitations of random phase shifts.
• Demonstrated superior accuracy in profile measurements compared to previous methods.
• Effective performance under high-noise conditions and with varying object heights.

Conclusions:

• The proposed tilt phase-shifting iterative method offers a robust solution for phase extraction in SRI.
• This approach enhances accuracy and reliability in challenging measurement scenarios.