Circularly-polarized, large-angle reflective deflectors based on periodically patterned cholesteric liquid crystals

Abstract

Patterned cholesteric liquid crystals enable the fabrication of circular-polarization sensitive, re ective di ractive optical elements based on Bragg re ection. Here we report the fabrication of large-angle re ective deector, which show de ection angles as large as 48.9°. The devices are fabricated by polarization holography, whereby two orthogonal circular polarized beams are superimposed on a photoalignment layer to create a linear modulation of the orientational easy axis. The devices show high circular-polarization extinction ratios, making them potentially useful as functional re ectors and polarization splitters.

17‐5: High Efficiency Polarization Volume Grating for Waveguide‐based AR Displays

“…The fabrication procedure of reflective PVGs device is proposed by Crawford et al [11]. To fabricate reflective PVGs, we spun coat photo-alignment material Brilliant yellow (0.4 wt%) dissolved in dimethylformamide (DMF) [9] onto cleaned glass substrates at 800 rpm for 5 s and then 3,000 rpm for 30 s to create uniform thin films on the substrates. The films were dried on a hotplate at 120 °C for 30 minutes.…”

“…Compared with heavy free-space combiner, extensive work on waveguide coupler has been devoted to achieving more compact designs [4][5][6]. Nevertheless, the state-of-the-art work on waveguide based AR [8,9] is still facing deflection angle and the efficiency limitations today. These cause insufficient applications of waveguide based combiner in AR devices.…”

Stretchable, flexible, and adherable polarization volume grating film for waveguide‐based augmented reality displays

“…Recent progresses in liquid‐crystal polarization volume grating (PVG) provide more possibility in waveguide‐based AR displays . Compared with conventional volume gratings used in AR devices, such as holographic volume gratings, PVGs can achieve nearly 100% first‐order efficiency at a very large diffraction angle, and moreover, they only respond to certain circularly polarized light.…”

“…Recent progresses in liquid-crystal polarization volume grating (PVG) provide more possibility in waveguide-based AR displays. [1][2][3][4][5] Compared with conventional volume gratings used in AR devices, such as holographic volume gratings, PVGs can achieve nearly 100% first-order efficiency at a very large diffraction angle, and moreover, they only respond to certain circularly polarized light. Besides these distinctive optical features, the elasticity of liquid crystal (LC) polymers [6][7][8][9] not only grants stretchability and flexibility 10 but also enables tunable periodicity for the diffractive optical elements.…”

59‐4: Fast‐response polarization volume gratings for AR/VR displays

“…Very recently, reflective polarization volume grating (PVG) based on self-organized chiral nematic (cholesteric) structure has been proposed and analyzed [1][2][3][4]. This type of polarization grating is effectively a Bragg grating because its rotation period in the optical axis is close to the light's wavelength along the propagation direction.…”