Meta-optics-based systems and methods for ocular applications
Meta-lens based ocular imaging, near-eye display, and eye-tracking systems are described. The systems can include a single focusing optic and an integrated circuit that provides illumination light and includes an imaging array. The focusing optic includes meta-atoms formed on a substrate. The systems may have no moving parts and achieve imaging or image-projection fields-of-view approaching or exceeding 180 degrees. Because of their low part count, the systems can be robust and have a very small form factor.
1 . A method of projecting an image or pattern into an eye with a display system that comprises a source of an image or pattern and a meta-surface, the method comprising:
forming an image or pattern projected from the source around an interior portion of an eye with the meta-surface, wherein:
the meta-surface comprises meta-atoms disposed on a substrate;
the image or pattern projected into the eye covers a field-of-view of at least 70 degrees around an interior of the eye; and
the meta-atoms comprise:
a plurality of cylindrical pillars disposed on a substrate, wherein the plurality of cylindrical pillars have at least eight different diameters less than the wavelength of light used to form the image or pattern and impart phase delays in a range from at least 50 degrees to 300 degrees to the light.
2 . The method of claim 1 , further comprising using the pupil of the eye as an aperture stop in the display system.
3 . The method of claim 1 , wherein the substrate has at least one curved surface.
4 . The method of claim 1 , wherein the substrate comprises at least one of sapphire, silica, calcium fluoride, chalcogenide, glass, semiconductor, or polymer.
5 . The method of claim 4 , wherein the meta-atoms are formed from at least one of a dielectric, semiconductor, or metal.
6 . The method of claim 1 , wherein the meta-atoms comprise meta-atoms of at least two different shapes or sizes that are repeated across the substrate.
7 . The method of claim 1 , further comprising providing multiplexed optical functions with at least a portion of the meta-atoms located in a same area of the meta-surface.
8 . The method of claim 7 , wherein providing multiplexed optical functions comprises:
illuminating a first region of the eye or projecting the image or pattern to the eye as a first optical function of the multiplexed optical functions; and
forming an image of the first region or of a second region of the eye as a second optical function of the multiplexed optical functions.
9 . The method of claim 1 , wherein the meta-atoms are first meta-atoms, and further comprising:
receiving, with a meta-optical element having second meta-atoms, optical rays from the meta-surface;
redirecting the optical rays, with the meta-optical element, to participate in forming the image or pattern; and
providing multiplexed optical functions with at least some of the second meta-atoms that are located in a same area of a meta-surface of the meta-optical element.
10 . The method of claim 1 , wherein the source comprises a light emitter, an emitter array or a micro-display.
11 . A method of projecting an image or pattern into an eye with a display system that comprises a source of an image or pattern and a meta-surface, the method comprising:
forming an image or pattern projected from the source around an interior portion of an eye with the meta-surface, wherein:
the meta-surface comprises meta-atoms disposed on a substrate, and
the image or pattern projected into the eye covers a field-of-view of at least 70 degrees around an interior of the eye;
receiving, with at least one optical element in the display system, optical rays from the meta-surface; and
redirecting the optical rays, by the at least one optical element, to participate in forming the image or pattern, wherein the at least one optical element comprises a meta-optic, a diffractive optical element, a holographic optical elements, a beam splitter, a refractive or reflective optic, or a waveguide.
12 . The method of claim 11 , further comprising:
combining, by the at least one optical element, the image or pattern from the source with other optical beams or a second image or pattern; and
projecting a combination of the image or pattern and the other optical beams or the second image or pattern to the eye.
13 . A method comprising:
emitting illumination light with an emitter;
projecting, with a first meta-surface located a first distance from a pupil of an eye, a pattern of the illumination light onto the eye, wherein:
the first meta-surface comprises a first plurality of meta-atoms disposed on a surface of a first substrate, and;
the first plurality of meta-atoms comprise:
a plurality of cylindrical pillars disposed on a substrate, wherein the plurality of cylindrical pillars have at least eight different diameters less than the wavelength of the illumination light used to form the pattern and impart phase delays in a range from at least 50 degrees to 300 degrees to the illumination light;
imaging, with a second meta-surface located a second distance from the pupil, a region of the eye illuminated by the pattern, wherein the second meta-surface comprises a second plurality of meta-atoms; and
recording an image of the region of the eye.
14 . The method of claim 13 , wherein a first area occupied by the first plurality of meta-atoms at least partially overlaps a second area occupied by the second plurality of meta-atoms.
15 . The method of claim 13 , further comprising providing multiplexed optical functions with at least the first plurality of meta-atoms.
16 . The method of claim 13 , wherein the second meta-surface is formed on a surface of a second substrate that is separated from the first substrate.
17 . The method of claim 13 , wherein at least the first meta-surface lies on a curved surface.
18 . The method of claim 13 , further comprising tracking movement of the eye based on at least the image of the region of the eye.
19 . The method of claim 13 , further comprising determining at least one of a gazing point of the eye, an orientation of the eye, or a position of the eye based on at least the image of the region of the eye.
20 . The method of claim 13 , wherein the image of the region of the eye comprises an image of at least one of a retina, pupil, palpebral, scleral, pars-planar, or iris of the eye.