Surface figure measurement tool based on a radial shearing interferometer using a geometric phase lens with various...

Area of Science:

• Optical Engineering
• Metrology
• Nanotechnology

Background:

• Surface figure measurement is critical for optical component performance.
• Traditional interferometers can be complex and limited in field of view.
• Geometric phase lenses offer unique polarization and diffraction properties.

Purpose of the Study:

• To develop a compact and efficient radial shearing interferometer for surface figure measurement.
• To leverage geometric phase lens characteristics for wavefront generation and analysis.
• To enable rapid and accurate reconstruction of optical component surface figures.

Main Methods:

• Utilizing a geometric phase lens to generate two radially sheared wavefronts.
• Employing a polarization pixelated complementary metal-oxide semiconductor camera to capture four phase-shifted interferograms.
• Adjusting the incident wavefront to match the target shape for planar reflected wavefronts.
• Reconstructing the surface figure from radial wavefront slope calculations.

Main Results:

• Successfully reconstructed surface figures of various optical components.
• Achieved measurement deviations of less than 0.78 µm over an extended measurement area.
• Demonstrated a fixed radial shearing ratio independent of the measured surface figures.
• Instantaneous reconstruction of the whole surface figure was enabled.

Conclusions:

• The compact radial shearing interferometer based on a geometric phase lens is a viable tool for precise surface figure measurement.
• The system offers advantages in speed, accuracy, and extended measurement capability.
• The method provides a robust approach for optical metrology applications.