Phase retrieval using axial diffraction patterns and a ptychographic iterative engine.

Area of Science:

• Optics and Photonics
• Computational Imaging
• Materials Science

Background:

• Phase retrieval is crucial for reconstructing object information from diffraction data.
• Conventional methods often face challenges with alignment and convergence speed.
• Ptychographic iterative engine (PIE) is a powerful algorithm for phase retrieval.

Purpose of the Study:

• To develop an advanced phase retrieval method using axial diffraction patterns.
• To improve the accuracy and efficiency of phase retrieval algorithms.
• To address challenges in aligning multiple diffraction patterns.

Main Methods:

• Utilizing axial diffraction patterns under planar and spherical wave illuminations.
• Implementing a ptychographic iterative engine (PIE) for phase retrieval.
• Developing a novel alignment adjustment method for multiple diffraction patterns.
• Employing random selection of measured diffraction patterns to accelerate PIE convergence.

Main Results:

• The proposed method demonstrates effective phase retrieval using multiple diffraction patterns.
• The alignment adjustment technique ensures accurate data integration.
• Random pattern selection significantly speeds up the optimization process.
• Simulations and optical experiments validate the method's effectiveness compared to conventional approaches.

Conclusions:

• The proposed phase retrieval method offers enhanced accuracy and efficiency.
• The technique is robust for both planar and spherical wave illuminations.
• This advancement has potential applications in various imaging and characterization fields.