Wave-front analysis with high accuracy by use of a double-grating lateral shearing interferometer

Area of Science:

• Optics and Photonics
• Interferometry
• Wave-front analysis

Background:

• Wave-front analysis is crucial for optical system characterization.
• Traditional interferometers can be sensitive to environmental disturbances.
• Improving the accuracy and reproducibility of wave-front measurement is an ongoing challenge.

Purpose of the Study:

• To present a phase-stepped double-grating lateral shearing interferometer for wave-front analysis.
• To analyze potential error sources and assess the achievable accuracy.
• To compare the performance of this new interferometer with a phase-stepped Twyman-Green interferometer.

Main Methods:

• Development and implementation of a phase-stepped double-grating lateral shearing interferometer.
• Analysis of interference patterns using a differential Zernike polynomial matrix-inversion method.
• Experimental testing and practical evaluation of the apparatus.

Main Results:

• The interferometer achieves an inaccuracy within 2-5 mλ root mean square (rms).
• Accuracy is comparable to that of a phase-stepped Twyman-Green interferometer.
• Lateral shearing interferometry demonstrates superior reproducibility due to its inherent stability and robustness.

Conclusions:

• The presented phase-stepped double-grating lateral shearing interferometer is a viable tool for accurate wave-front analysis.
• The method offers a robust and reproducible alternative to existing interferometric techniques.
• The design effectively minimizes errors, ensuring reliable optical metrology.