Fourier transform demodulation of pixelated phase-masked interferograms

Area of Science:

• Optics and Photonics
• Interferometry
• Image Processing

Background:

• A new spatial phase shifting interferometer utilizes a phase-mask over camera pixels for independent modulation.
• Standard interferometers employ a 2x2 array phase-shift pattern across the CCD, limiting flexibility.

Purpose of the Study:

• To propose a new phase demodulation method for phase-masked interferograms.
• To leverage squeezing phase-shifting techniques for enhanced interferometric analysis.
• To introduce an alternative phase-mask for spatial carrier modulation.

Main Methods:

• Phase demodulation of phase-masked interferograms using squeezing phase-shifting.
• Application of Fourier interferometry to eliminate detuning errors.
• Utilizing a linear polarizer integrated with the camera's CCD for pixel-level phase modulation.

Main Results:

• The proposed squeezing technique enables effective phase demodulation.
• Fourier interferometry successfully eliminates detuning errors common in other phase-shifting algorithms.
• An alternative phase-mask design for linear spatial carrier modulation is suggested.

Conclusions:

• Squeezing phase-shifting offers an advantageous method for analyzing phase-masked interferograms.
• The technique enhances accuracy by mitigating detuning errors, particularly with Fourier interferometry.
• Alternative phase-mask designs can further optimize spatial phase modulation in interferometry.