Hybrid design of diffractive optical elements for optical beam shaping.

Area of Science:

• Optics and Photonics
• Computational Electromagnetics

Background:

• Diffractive optical elements (DOEs) are crucial for manipulating light.
• Traditional design methods face challenges with complex irradiance patterns and fabrication.

Purpose of the Study:

• To develop a novel geometrical-optics method for calculating eikonal functions for DOE design.
• To enable the generation of complex and discontinuous irradiance distributions.
• To facilitate the creation of fabrication-friendly DOEs.

Main Methods:

• A semi-discrete geometrical-optics approach formulated as a concave function maximization problem.
• Utilized a gradient-based method with analytical gradient expressions.
• Employed a hybrid approach combining geometrical optics with iterative Fourier transform algorithms.

Main Results:

• Successfully calculated an eikonal function for generating a discontinuous hexagram irradiance distribution.
• Demonstrated the ability to design DOEs with quasi-regular or piecewise-smooth microrelief.
• Experimental validation confirmed the design and performance of the fabricated DOE.

Conclusions:

• The proposed geometrical-optics method offers a powerful tool for designing high-performance DOEs.
• This approach overcomes limitations of previous methods, allowing for complex irradiance patterns.
• The hybrid method facilitates the fabrication of intricate DOE structures.