Design of two compact waveguide display systems utilizing metasurface gratings as couplers

Abstract

We propose two approaches to design compact head mount display (HMD) systems employing metasurface gratings. In the first approach, we design and simulate a monocular optical waveguide display by applying crystalline-silicon elliptical-shaped metasurface arrays as couplers on a right trapezoid waveguide to achieve large field of view (FOV) horizontally. As such, we achieve a FOV as large as 80° that is approximately 80% higher than the FOV in traditional waveguide systems based on diffractive gratings. In the second approach, considering the polarization sensitivity feature in metasurfaces and employing the proposed structures in the first technique, we design a metasurface grating as the input coupler in a binocular HMD system. The suggested structure diffracts incident light into two opposite directions with a 53.7° deflection angle on each side. We use the finite difference time domain method to study the behavior of the proposed systems.

Metasurface-based augmented reality headset equipped with an eye movement monitoring system

“…In this part, the simulation results of gratings in the two systems under TE polarization at wavelength 635 nm and 775 nm are demonstrated. In (Afra et al 2021), the variation of diffraction angle and diffraction e ciency in both couplers are studied. As seen in the Fig.…”

“…(7) and Fig. ( 8) in (Afra et al 2021), the diffraction e ciencies in both coupler in AR system at wavelength 635 nm in the range of 0 to 44 dgerees are rather uniform that make them appropriate to realize clear image in AR section.…”

“…4. (a) in (Afra et al 2021). In the proposed eye tracker system, the suggested structures for MGI2 and MGO2 gratings consist of periodic arrays of three elliptical C-silicon nano-elements with the same thicknesses and 120 phase shifts which their radius R x increase gradually in the X direction, while their radius R Y are xed in this direction.…”

“…For designing the shape of the waveguide in this approach, we have used the suggested idea in (Afra et al 2021). In this reference, the design procedure of the waveguide and metasurface couplers are extensively explained.…”

“…In this paper, another optical part is added to the previous design (Afra et al 2021) in order to equip the proposed metasurface-based waveguide display system with an eye gaze direction monitoring technology. The suggested system comprises two completely distinguished sections; the rst part consists of a right trapezoid waveguide and two couplers to acts as an AR system at wavelengths 635 nm, while the other section includes a right trapezoid waveguide and two couplers operate as an eye tracker system at wavelength 775 nm.…”