Slope measurement of a phase object using a polarizing phase-shifting high-frequency Ronchi grating interferometer

Area of Science:

• Optical Metrology
• Interferometry
• Phase Measurement

Background:

• Measuring the slope of phase objects is crucial in various scientific and engineering fields.
• Traditional interferometric methods can be complex and require extensive data acquisition.

Purpose of the Study:

• To present a novel interferometric method for efficiently measuring the slope of phase objects.
• To demonstrate the capability of a polarizing phase-shifting cyclic shear interferometer coupled with a 4-f Fourier imaging system.

Main Methods:

• Implementation of a polarizing phase-shifting cyclic shear interferometer.
• Coupling with a 4-f Fourier imaging system and crossed high-frequency Ronchi gratings.
• Acquisition of nine interference patterns with adjustable phase shifts and variable lateral shear.

Main Results:

• The system successfully obtains nine interference patterns.
• Analysis using only four patterns from a single shot enables slope extraction.
• The classical method of phase extraction is applied effectively.

Conclusions:

• The presented interferometric method provides an efficient way to measure phase object slopes.
• The combined system offers adjustable phase shifts and variable lateral shear for versatile analysis.
• Single-shot analysis with four patterns simplifies the measurement process.