Reflective polarization volume gratings for high efficiency waveguide-coupling augmented reality displays.

We demonstrate a reflective liquid-crystal polarization volume grating with high efficiency for augmented reality displays. The coupling efficiency was measured to be 90% at 650 nm and 50° deflection angle. The angular dependence of reflection band agrees well with Bragg condition, and the transmittance of environment light is high with negligible scattering. The bandwidth can be tailored by controlling the layer periodicity, allowing versatile applications and design freedom not only for augmented realities but also for other photonic devices.