Sparse holographic imaging for an integrated augmented reality near-eye display

Abstract

Diffraction is the main physical effect involved in the imaging process of holographic displays. In the application of near-eye displays, it generates physical limits that constrain the field of view of the devices. In this contribution, we evaluate experimentally an alternative approach for a holographic display based mainly on refraction. This unconventional imaging process, based on sparse aperture imaging, could lead to integrated near-eye displays through retinal projection, with a larger field of view. We introduce for this evaluation an in-house holographic printer that allows the recording of holographic pixel distributions at a microscopic scale. We show how these microholograms can encode angular information that overcomes the diffraction limit and could alleviate the space bandwidth constraint usually associated with conventional display design.

Evaluation of a pixelated holographic display concept for a near-eye display: recent results and technological developments

“…With these characteristics, the hoel distributions constitute a holographic display that forms images in a non-conventional way 15 . Figure 2(c) describes the principle of this display.…”

“…These beams are phaseadjusted so that the spherical wavefronts they produced form a composite planar wavefront in the far field according to the Huygens Fresnel principle. The direction of propagation  is created through a refractive process and then can exceed the diffraction limit Ray 15 . This is a specific behavior of the concept, which distinguishes it from classical approaches to holographic displays.…”

“…On the object arm of the interferometer, the incidence of the beam on the mask is changed after each recording. Various recording strategies can be used to record the hoel distributions 15 . We give in Figure 4 The recovery of the hologram is made in a setup that reproduces the NED configuration.…”

Flexible holographic metasurfaces for augmented reality near-eye display

“…Traditional AR technologies often come with bulky optical components, unlike the lightweight nature of regular glasses [1]. Integrating Near-Eye Display (NED) technology into conventional eyewear, especially those with prescriptions, poses significant challenges [2]. NED has become a critical platform for AR applications, with recent advances made by integrating innovative photonic technologies like grating waveguides [3,4], surface relief gratings (SRGs) [5], and metasurfaces (MSs) [6,7].…”

Directional display for AR applications based on holography and photonic integrated circuits

“…These µ-displays do not allow for control over the emission properties, resulting in low power efficiency in the AR system, or a limited EyeBox (EB) and Field of View (FoV). This paper introduces an innovative display concept that uses photonic integrated circuits (PICs) in the visible range [8], [9], combined with active light extraction components using liquid crystals [10], [11] and pixelated holograms [12], [13]. This new approach aims to offer a more flexible integration with the optical combiner and to increase the energy efficiency of AR glasses.…”