Liquid-crystal-based polarization volume grating applied for full-color waveguide displays.

Area of Science:

• Optics and Photonics
• Materials Science
• Display Technology

Background:

• Near-eye displays require efficient light-coupling mechanisms for full-color imaging.
• Traditional waveguide displays face challenges in achieving wide fields of view and high optical efficiency.
• Polarization-sensitive optical elements are crucial for advanced display functionalities.

Purpose of the Study:

• To demonstrate polarization volume grating (PVG)-based couplers for double-layer waveguide displays.
• To realize a full-color near-eye display with high performance characteristics.
• To investigate the potential of chiral-dopant reactive mesogen materials for display applications.

Main Methods:

• Fabrication of PVG couplers using polarized interference exposure and photo-alignment techniques.
• Generation of a birefringent spiral configuration with 2D periodicity in a chiral-dopant reactive mesogen.
• Characterization of diffraction efficiency, diffraction angles, and optical performance across blue, green, and red spectra.

Main Results:

• PVG couplers achieved over 80% diffraction efficiency with large diffraction angles for blue, green, and red light.
• A waveguide prototype demonstrated a full-color display with a diagonal field of view of approximately 35°.
• High overall optical efficiency (118.3 cd/m² per lumen) and 72% transparency for ambient light were recorded.

Conclusions:

• PVG-based couplers are highly efficient and polarization-selective elements for waveguide displays.
• The developed technology enables high-performance full-color near-eye displays with a wide field of view.
• This approach offers a promising solution for advanced augmented reality and virtual reality systems.