Quantitative birefringence distribution measurement using mixed-state ptychography.

Area of Science:

• Optics and Photonics
• Materials Science
• Crystallography

Background:

• Ptychography is a powerful lensless imaging technique, but measuring the complete optical behavior of anisotropic samples remains challenging.
• Existing methods for characterizing anisotropic materials often involve complex setups or multiple scans, limiting efficiency and accuracy.

Purpose of the Study:

• To develop a novel and efficient method for measuring the birefringence of anisotropic samples.
• To simultaneously determine the azimuth angle and retardation of anisotropic materials in a single ptychography scan.

Main Methods:

• A mixed-state ptychography approach was employed, utilizing a reference system transformation to retrieve two orthogonal object states.
• This method allows for unambiguous reconstruction of sample properties and significant error reduction.

Main Results:

• The proposed method achieved high accuracy, with normalized root mean square errors of 0.0011 for azimuth angle and 0.0041 for retardation.
• Simultaneous acquisition of both parameters was demonstrated in a single scan.

Conclusions:

• The novel mixed-state ptychography method provides a rapid, accurate, and simplified approach for optical characterization of anisotropic samples.
• This technique offers advantages over traditional interferometric methods, including an unlimited field of view and a more stable setup, opening new avenues for material investigation.