Design of diffractive phase elements that produce focal annuli: a new method.

Area of Science:

• Optics and Photonics
• Diffractive Optics
• Computational Imaging

Background:

• Diffractive phase elements (DPEs) are crucial for manipulating light beams.
• Designing DPEs to generate specific light patterns, like focal rings, is challenging.
• Existing algorithms may have limitations in performance and robustness.

Purpose of the Study:

• To propose a new optimization method for designing DPEs.
• To enable the creation of precise focal annular patterns from uniform beams.
• To compare the new method with the Gerchberg-Saxton algorithm and assess quantization effects.

Main Methods:

• Utilizing the general theory of amplitude-phase retrieval.
• Developing a set of equations for DPE phase distribution.
• Employing an iterative algorithm for surface-relief DPE profile design.
• Conducting numerical simulations and performance comparisons.

Main Results:

• The proposed method successfully designs DPEs for focal annular patterns.
• Numerical examples demonstrate the algorithm's effectiveness.
• Comparison shows advantages over the Gerchberg-Saxton algorithm.
• Quantization effects on DPE performance were investigated.

Conclusions:

• The new amplitude-phase retrieval-based optimization method is effective for DPE design.
• It enables efficient conversion of uniform beams into focal annular patterns.
• The method shows robustness against phase quantization, enhancing practical applicability.