System design and error correction of simultaneous phase-shifting point-diffraction interferometer for dynamic...

Area of Science:

• Optical Engineering
• Interferometry
• Wavefront Sensing

Background:

• Accurate dynamic wavefront measurement is crucial for optical system testing.
• Existing interferometers face challenges with large apertures and dynamic wavefronts.
• Simultaneous phase-shifting techniques offer advantages for dynamic measurements.

Purpose of the Study:

• To design and develop a simultaneous phase-shifting point-diffraction interferometer (SPS-PDI) for dynamic wavefront detection.
• To enable the measurement of large-aperture (400 mm) dynamic wavefronts with high precision.
• To introduce and validate novel methods for error suppression in interferometry.

Main Methods:

• Design of an SPS-PDI utilizing an off-axis parabolic mirror (OAPM).
• Development of a polarization point-diffraction plate (P-PDP) for simultaneous phase modulation.
• Implementation of a chessboard phase grating and retarder array for acquiring four phase-shifting interferograms.
• Application of circular carrier squeezing interferometry (CCSI) to mitigate phase errors.

Main Results:

• Successful design and implementation of the SPS-PDI system operating at 632.8 nm.
• Demonstration of dynamic wavefront detection capability for a 400 mm aperture.
• Achieved high accuracy, with peak-to-valley (PV) and root-mean-square (RMS) differences of 0.04λ and 0.008λ compared to a commercial dynamic interferometer.
• Validation of CCSI for suppressing position mismatch, intensity distortion, and phase-shift errors.

Conclusions:

• The developed SPS-PDI system effectively measures dynamic wavefronts with high precision and accuracy.
• The integration of OAPM, P-PDP, and CCSI provides a robust solution for challenging wavefront sensing applications.
• The system demonstrates excellent performance and consistency with established dynamic interferometers.