We have previously shown through simulation that an optical beam deflector based on the Pancharatnam (geometric) phase can provide high efficiency with up to 80° deflection using a dual-twist structure for polarization-state control [Appl. Opt.54, 10035 (2015)]. In this report, we demonstrate that its optical performance is as predicted and far beyond what could be expected for a conventional diffractive optical device. We provide details about construction and characterization of a ± 40° beam-steering device with 90% diffraction efficiency based on our dual-twist design at a 633nm wavelength.
Lenses based on the Pancharatnam phase have the advantage of being thin and inexpensive. Unfortunately, their optical effect is strongly wavelength dependent, and their applications generally are limited by the requirement of a monochromatic source. However, low-power lenses based on the Pancharatnam phase can be considered for applications over the visible range. In this paper, we provide intuitive "limits" for the lens power, below which these devices can be considered for use with the eye and visible light imaging applications.
We present a nonmechanical zoom lens system based on the Pancharatnam phase effect, which is controlled by the state of circularly polarized light. The device is shown to allow for a compact design for a wide range of zoom ratios. A demonstration system is shown, which has a 4× zoom ratio between its two electrically switchable states. We show its observed image quality experimentally and compare it with calculated expectations.
Accommodation-convergence mismatch is still an unsolved issue within the field of augmented reality, virtual reality, and three-dimensional systems in general. Solutions suggested to correct the focus cue in recent years require additional bandwidth, or compromise the image resolution. Our simple approach to overcome this issue is by using an eye-tracking system and electronic lenses. We propose an electronic hybrid lens system composed of segmented phase profile liquid crystal and Pancharatnam phase lenses. For practical application, eye tracking is necessary for measuring the toe-in of the user's pupil to calculate the object depth. This information is used to determine the required diopteric power of the hybrid system. The optical performance and imaging quality of the proposed hybrid system are evaluated.
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