Polarization volume grating with high efficiency and large diffraction angle

Abstract

We propose a polarization volume grating (PVG), which exhibits nearly 100% diffraction efficiency and large diffraction angle. Both reflective and transmissive PVGs can be configured depending on application preference. Such a PVG is polarization-sensitive so that it can split an incident unpolarized beam into two well-separated yet polarized beams. These outstanding features make PVG a strong candidate for photonic and display applications. To investigate and optimize the diffraction properties, we build a rigorous simulation model based on finite element method. To illustrate its potential applications, we propose a simple 2D/3D wearable display using a planar waveguide comprising of two reflective PVGs.

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

“…Linear polarization gratings with a period as small as 0.84 µm were fabricated, resulting in a di raction angle of 48.9°at a wavelength of 640 nm. In line with theoretical predictions [16], a high CP selectivity was observed, making these devices feasible as high-e ciency, semi-transparent re ectors and polarization splitters.…”

“…3. The di raction e ciencies of the samples for RCP were measured to be 27.8%, 31.9% and 24.1% for γ = 5°, 10°and 15°, respectively, which is considerably lower than the near-100% e ciency predicted numerically [16]. However, considering that all samples showed~40% reectance when the spectrum was measured at the region with a clear polarization grating (Fig.…”

“…4), higher e cien- ies should be achievable by improving the interference setup to fabricate more uniform devices and applying antire ection coatings on top of the devices. reality (VR) devices and polarization splitters in wearable 3D displays [16]. Figure 7(a) shows the angular dependence of light reection for the γ = 15°sample at various incidence angles.…”

Recent progress in Pancharatnam–Berry phase optical elements and the applications for virtual/augmented realities

“…In addition to transmission-type de ector, a re ective polarization volume grating (RPVG) [35,47], which incor-porates a higher degree of twist along z-axis (i.e., much smaller pz, as shown in Fig. 13(a)) can be con gured as well.…”

“…As shown in Fig. 14, Weng et al [35] proposed an exemplary setup, by switching between LCP and RCP through a polarization rotator disposed on the output side of the display panel, light can be guided to the user's left and right eyes in a time sequential manner. Therefore, it reduces the number of display panel needed for the headset, allowing a smaller form factor.…”