Light-field imaging using a gradient metasurface optical element
Embodiments of 3D imaging systems that use a multifunctional, nano structured metalens to replace the conventional microlens array in light field imaging are disclosed. The optical focusing properties of the metalenses provided by gradient metasurface optical elements. The gradient metasurfaces allow the properties of the elements of the metalens array to be changed by tuning the gradient metasurfaces.
1. A multiplexed metalens array for a light-field imaging system comprising:
a multiplexed dielectric gradient metasurface optical element;
wherein the multiplexed dielectric gradient metasurface optical element comprises a plurality of optical sub-elements that are each a subset of the multiplexed gradient metasurface optical element;
wherein each optical sub-element is divided into segments that are arranged in a nonperiodic pattern along the surface plane of the multiplexed gradient metasurface optical element such that each sub-element is dispersed and spatially interleaved with the other sub-elements into an integrated array, wherein the arrangement of each sub-element's segments results in a shared effective aperture among the subelements; and
wherein each sub-element is configured to have a unique phase response such that each sub-element has a unique optical axis and focuses light derived from an object onto an image plane at a particular spatial location such that multiple perspectives of the object can be perceived on the image plane.
2. The multiplexed metalens array of claim 1 wherein at least two of the plurality of sub-elements have a different numerical aperture.
3. The multiplexed metalens array of claim 1 wherein at least two of the plurality of elements have a different focal length.
4. The multiplexed metalens array of claim 1 wherein each of the plurality of sub-elements have a coded aperture with additional phase modulation or an amplitude modulation incorporated therein.
5. The multiplexed metalens array of claim 1 wherein the plurality of sub-elements manipulate different states of polarization.
6. The multiplexed metalens array of claim 1 wherein the sub-elements are constructed with silicon nanobeam antennas; and wherein the phase response of each sub-element is based on geometric phase generated by the silicon nanobeam antennas.
7. The multiplexed metalens array of claim 1 wherein the plurality of sub-elements include N sub-elements and an intensity, I, of an image generated decreases as a function of N, wherein I˜1/N 2 .
8. The multiplexed metalens array of claim 1 wherein the phase response of each sub-element produces a unique focal point such that an array of focal points is projected onto the image plane when illuminated with light derived from the object when the object is placed at infinity.
9. The multiplexed metalens array of claim 1 wherein the phase response of each sub-element is a light scattering phase response.
10. The multiplexed metalens array of claim 1 wherein the effective aperture of at least one sub-element is equal to the effective aperture equal of the full multiplexed dielectric gradient metasurface optical element.
11. The multiplexed metalens array of claim 1 wherein the multiplexed dielectric gradient metasurface optical element is incorporated into a light imaging system; and wherein the light imaging system includes at least one tube lens wherein one of the at least one tube lens is associated with one of the plurality of sub-elements to project an image from the one of the plurality of sub-elements onto a focal plane.
12. The multiplexed metalens array of claim 11 wherein the plurality of sub-elements includes N sub-elements and the at least one tube lens includes N tube lenses and each of the N sub-elements is associated with one of the N lens tubes to project the image from the one element onto the focal plane.
13. The multiplexed metalens array of claim 11 wherein the plurality of sub-elements includes N sub-elements and the at least one tube lens includes one lens tube and each of the N sub-elements is associated with the one tube lens to project an image onto the focal plane.
14. The multiplexed metalens array of claim 11 wherein at least two of the plurality of sub-elements have a different numerical aperture.
15. The multiplexed metalens array of claim 11 wherein at least two of the plurality of elements have a different focal length.
16. The multiplexed metalens array of claim 11 wherein each of the plurality of sub-elements have a coded aperture with additional phase modulation or an amplitude modulation incorporated therein.
17. The multiplexed metalens array of claim 11 wherein the plurality of sub-elements manipulate different states of polarization.
18. The multiplexed metalens array of claim 11 wherein the sub-elements are constructed with silicon nanobeam antennas; and wherein the phase response of each sub-element is based on geometric phase generated by the silicon nanobeam antennas.
19. The multiplexed metalens array of claim 11 wherein the plurality of sub-elements include N sub-elements and an intensity, I, of an image generated decreases as a function of N, wherein I˜1/N 2 .
20. The multiplexed metalens array of claim 11 wherein the phase response of each sub-element produces a unique focal point such that an array of focal points is projected onto the image plane when illuminated with light derived from the object when the object is placed at infinity.
21. The multiplexed metalens array of claim 11 wherein the phase response of each sub-element is a light scattering phase response.