Optimal design of depth-scaling error for multilayer diffractive optical elements with oblique incidence

Area of Science:

• Optics and Photonics
• Materials Science

Background:

• Multilayer diffractive optical elements (MLDOEs) are crucial for advanced optical systems.
• Depth-scaling error is a critical manufacturing parameter affecting MLDOE performance.
• Oblique incidence and polychromatic light introduce complexities in MLDOE design.

Purpose of the Study:

• To develop mathematical analytic models for depth-scaling error in MLDOEs under oblique incidence.
• To establish a method for the optimal design of depth-scaling error considering comprehensive polychromatic integral diffraction efficiency (PIDE).
• To analyze the impact of depth-scaling error on diffraction efficiency and PIDE for MLDOEs in the visible spectrum.

Main Methods:

• Development of mathematical analytic models relating depth-scaling error to diffraction efficiency and PIDE.
• Formulation of an optimal design method for depth-scaling error.
• Analysis of MLDOE performance across a range of incident angles (0-20°) and visible wavelengths.

Main Results:

• The study quantifies the relationship between depth-scaling error and diffraction efficiency/PIDE for MLDOEs.
• An optimal relative depth-scaling error of -6.55% was identified for maximum comprehensive PIDE.
• A maximum comprehensive PIDE of 98.24% was achieved for MLDOEs operating within 0-20° incident angles.

Conclusions:

• The developed analytic method provides a theoretical foundation for determining manufacturing tolerances for depth-scaling error in MLDOEs.
• Optimal depth-scaling error is essential for maximizing PIDE in MLDOEs under oblique incidence.
• This research aids in the precise fabrication of MLDOEs for demanding optical applications.