Single-Shot Imaging of Two-Wavelength Spatial Phase-Shifting Interferometry

Area of Science:

• Optical Metrology
• Surface Characterization
• 3D Imaging

Background:

• Traditional phase-shifting interferometry faces limitations with 2π-ambiguity and slow measurement speeds.
• Accurate 3D surface profiling is crucial for quality control and material science.

Purpose of the Study:

• To develop an effective single-shot method for measuring 3D surface profiles.
• To address the 2π-ambiguity problem inherent in phase-shifting interferometry.
• To enable rapid and accurate surface characterization of specimens.

Main Methods:

• Utilizing the two-wavelength interferometric principle.
• Implementing a spatial phase-shifting technique with a polarization pixelated camera.
• Calculating rough surface profiles using interference fringe visibility.
• Compensating for height discontinuities via phase jumps in fine height maps.

Main Results:

• Successful rapid phase measurement.
• Overcame the 2π-ambiguity problem.
• Validated measurement of continuously smooth surfaces and large step heights (9 μm).
• Results showed good agreement with established two-wavelength interferometry.

Conclusions:

• The proposed single-shot method provides an effective solution for 3D surface profiling.
• The technique accurately measures complex surfaces, including rough textures and significant height variations.
• This advancement offers a faster and more robust alternative to conventional interferometric methods.