Design of off-axis reflective imaging systems based on freeform holographic elements

Area of Science:

• Optics and Photonics
• Optical Engineering
• Holography

Background:

• Holographic optical elements (HOEs) offer unique advantages in optical systems, including thin profiles and selective light manipulation.
• Freeform optics provide extensive design flexibility, enabling complex wavefront control and aberration correction.

Purpose of the Study:

• To propose and validate a design methodology for off-axis reflective imaging systems utilizing freeform HOEs.
• To demonstrate the effectiveness of this method through the design and fabrication of a head-up display system.

Main Methods:

• A point-by-point design approach was employed for initial system and HOE recording system generation.
• Joint optimization was performed, considering imaging performance, diffraction efficiency, system constraints, and fabrication.
• A prototype off-axis reflective head-up display system was designed and fabricated to validate the method.

Main Results:

• The proposed method enables the design of off-axis reflective imaging systems with freeform HOEs.
• The developed freeform HOEs effectively correct aberrations in nonsymmetric systems.
• A functional head-up display prototype demonstrated the feasibility and effectiveness of the design approach.

Conclusions:

• Freeform HOEs significantly enhance the design possibilities for off-axis reflective imaging systems.
• The integrated design and optimization method is effective for creating high-performance optical systems.
• This work paves the way for advanced optical designs in head-up displays and other applications.