Fast-switchable polarization-dependent bifocal lenses for AR displays

Abstract

Polarization-dependent bifocal Pancharatnam-Berry phase lenses are proposed to integrate designable bifocal functionality into a single compact device. These lenses are fabricated using photoalignment techniques with a patterned light field generated by a spatial light modulator and are designed in both longitudinal and transverse configurations to address critical challenges in AR displays. The longitudinal configuration resolves the vergence-accommodation conflict by enabling multi-plane displays, while the transverse configuration extends the field-of-view (FOV) through dual horizontal FOVs. A key innovation in this system is the incorporation of an electrically suppressed helix ferroelectric liquid crystal (ESHFLC) polarization rotator, which enables rapid switching between dual depths or FOVs with a response time of 35 μs. The performance of the designed flat lenses and ESHFLC polarization rotator is thoroughly characterized. As a proof of concept, the integrated system is successfully demonstrated for AR display applications, showcasing dual-depth imaging and extended FOV capabilities. This compact and efficient solution addresses key challenges in AR displays, enabling true 3D multi-plane displays and extending the FOV for next-generation AR systems.