Design of single-layer color echelle grating optical waveguide for augmented-reality display

Area of Science:

• Optics
• Photonics
• Display Technology

Background:

• Augmented reality (AR) displays require efficient and compact optical systems.
• Traditional AR optical systems often face challenges with size, efficiency, and field of view.

Purpose of the Study:

• To propose and analyze a single-layer color echelle grating combined optical waveguide structure for AR displays.
• To optimize the grating parameters for efficient light manipulation and a wide field of view.

Main Methods:

• Utilized echelle gratings with super-wavelength periodic scale as key optical elements.
• Employed vector diffraction theory to optimize structural parameters and tolerance ranges.
• Achieved combined propagation of RGB primary colors through overlapping high diffraction orders.

Main Results:

• Attained average diffraction efficiencies exceeding 74% (in-coupling), 21% (relay), and 35% (out-coupling) for RGB colors.
• Demonstrated dual-channel one-dimensional pupil dilation.
• Achieved a field-of-view angle of 18.9° (horizontal) × 36.87° (vertical).

Conclusions:

• The proposed single-layer structure offers a viable solution for compact and efficient AR display optics.
• The optimized echelle gratings enable high-performance light manipulation for AR applications.
• The achieved field of view and diffraction efficiencies meet key requirements for advanced AR systems.