Metalens Eyepiece for 3D Holographic Near-Eye Display.

Chang Wang,Zeqing Yu,Qiangbo Zhang,Fei Wu,Zhenrong Zheng,Yan Sun,Chenning Tao

doi:10.3390/nano11081920

Chang Wang, Zeqing Yu + Show 5 more

Open Access

https://doi.org/10.3390/nano11081920

Copy DOI

Abstract

Near-eye display (NED) systems for virtual reality (VR) and augmented reality (AR) have been rapidly developing; however, the widespread use of VR/AR devices is hindered by the bulky refractive and diffractive elements in the complicated optical system as well as the visual discomfort caused by excessive binocular parallax and accommodation-convergence conflict. To address these problems, an NED system combining a 5 mm diameter metalens eyepiece and a three-dimensional (3D), computer-generated holography (CGH) based on Fresnel diffraction is proposed in this paper. Metalenses have been extensively studied for their extraordinary capabilities at wavefront shaping at a subwavelength scale, their ultrathin compactness, and their significant advantages over conventional lenses. Thus, the introduction of the metalens eyepiece is likely to reduce the issue of bulkiness in NED systems. Furthermore, CGH has typically been regarded as the optimum solution for 3D displays to overcome limitations of binocular systems, since it can restore the whole light field of the target 3D scene. Experiments are carried out for this design, where a 5 mm diameter metalens eyepiece composed of silicon nitride anisotropic nanofins is fabricated with diffraction efficiency and field of view for a 532 nm incidence of 15.7% and 31°, respectively. Furthermore, a novel partitioned Fresnel diffraction and resample method is applied to simulate the wave propagations needed to produce the hologram, with the metalens capable of transforming the reconstructed 3D image into a virtual image for the NED. Our work combining metalens and CGH may pave the way for portable optical display devices in the future.

Highlights

Published: 26 July 2021Metasurfaces are arrays of subwavelength dielectric or metallic antennas and have been widely investigated for their remarkable capabilities to manipulate the phase, amplitude, and polarization state of the incident light [1]
The field of view (FOV) of the system is determined by the eyepiece size as well as the eye relief distance, rather than by the display size, which results in the metalens eyepiece being superior to conventional eyepieces [16], and the corresponding FOV can be expressed as 2 tan−1 [Am /(2de )], where Am is metalens eyepiece aperture
The subsequent fabrication processes are carried out as follows: the growth of a 400 nm thick Si3N4 layer on a double-polished quartz plate is prepared by using plasma-enhanced chemical vapor deposition (PECVD), and subse

Summary

Introduction

Metasurfaces are arrays of subwavelength dielectric or metallic antennas and have been widely investigated for their remarkable capabilities to manipulate the phase, amplitude, and polarization state of the incident light [1] Due to their extraordinary performances in wavefront shaping, metasurfaces have been used to miniaturize various traditional optical elements into ultrathin devices, such as metalens [2,3,4,5,6,7], meta-hologram [8,9], vortex beam generator [10,11], and wave plate [12,13]. Thin optical eyepieces such as metalenses [14,16], diffractive optical elements (DOE) [17], and holographic optical elements (HOE) [18] have been investigated for their ability to miniaturize optical systems, Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Methods

Results

Conclusion