Shifting of localization planes in optical testing: application to a shearing interferometer.

Area of Science:

• Optics and Photonics
• Interferometry
• Materials Science

Background:

• Amplitude-division interferometers with quasi-monochromatic, spatially incoherent, and periodic sources produce multiple interference fringe localization planes.
• Analyzing layered materials with localized phase disturbances presents challenges in conventional imaging techniques.

Purpose of the Study:

• To develop and demonstrate a method for analyzing localized phase disturbances in different layers of a thick transmission sample using an interferometer.
• To show that different layers can be selectively analyzed by shifting the localization plane through source period variation.

Main Methods:

• Utilized an amplitude-division two-beam interferometer illuminated by a periodic source.
• Introduced a thick transmission sample with localized phase disturbances.
• Employed a shearing interferometer configuration with a Wollaston prism and crossed polarizers.
• Varied the source period to shift the localization plane for analyzing different sample layers.

Main Results:

• Successfully detected localized phase disturbances within specific layers of the sample.
• Demonstrated that images from different layers could be made to coincide with a chosen localization plane.
• Obtained experimental images of different observation planes that matched theoretical predictions.

Conclusions:

• The proposed method enables layer-selective analysis of phase disturbances in thick samples.
• Shifting the localization plane via source period modification is an effective, non-invasive technique for analyzing multi-layered materials.
• The technique shows good agreement between experimental results and theoretical models, validating its utility.