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

Abstract

Abstract:In this review paper, we report recent progress on Pancharatnam-Berry (PB) phase optical elements, such as lens, grating, and de ector. PB lenses exhibit a fast switching time between two or more focal lengths with large diopter change and aperture size, which is particularly attractive for addressing the accommodation mismatch in head-mounted display devices. On the other hand, PB gratings and de ectors o er a large-angle beam de ection with wide acceptance cone and high e ciency, as compared to conventional volume gratings. Such merits provide great advantages for waveguide-coupling augmented reality headsets. Moreover, the thickness of PB optical elements is only a few micrometers, thus they can be conveniently integrated into modern wearable display systems.

Multiplane displays based on liquid crystals for AR applications

“…For example, a thin‐cell TN device with response time of approximately 2 ms has been used in polarization multiplexing multiplane AR displays as a broadband polarization rotator . Wu et al used a tunable PB LC lens that can achieve a response time as fast as 0.7 ms in their AR display system . We have fabricated PSLC shutters that could be switched between transparent and scattering states with submillisecond response time, which enables relatively large number of image planes …”

“…The key components of multiplane displays using the time‐multiplexing method are fast tunable optical devices, such as liquid lens, deformable mirror, and liquid crystal (LC) devices . For instance, Hua et al realized a multiplane optical see‐through (OST) AR display utilizing a tunable liquid lens.…”

“…For example, LC polarization switches, together with polarization selective devices such as a savart plate, a polarizing beam splitter, calcite lens, or cholesteric LC (CLC) films, are used for time‐multiplexed AR systems to generate images at different depths. Tunable LC lenses (eg, LC refractive lens and LC Pancharatnam‐Berry [PB] lens) are employed in AR displays, to control the distance of virtual images by varying their focal lengths. And in some displays, multiple LC scattering shutters are used as the display medium …”

Compact see‐through near‐eye display with depth adaption

“…On the other hand, a transmissive PBL is essentially a patterned half‐wave plate (Fig. (a)) with encoded parabolic phase profile . A PBL can focus or defocus the light, depending on the handedness of the input circularly polarized light.…”

Programmable Zoom Lens System with Two Spatial Light Modulators: Limits Imposed by the Spatial Resolution

“…Programmable active lenses are currently available with different technologies, including liquid lenses [3], liquid-crystal lenses [4,5], or active polymer lenses [6]. Pancharatnam-Berry (PB) lenses are a new technology useful to overcome the slow response time of other technologies [7]. Therefore, zoom lenses with tunable adjustment and no moving elements have been reported [8][9][10][11].…”