Shared-aperture camera system and calibration method
Disclosed herein is various shared-aperture camera systems and calibration methods. One particular shared-aperture camera system includes a polarization imaging device including: an aperture; a first metasurface configured to diffract incident light going through the aperture such that a first polarization of incident light diffracts in a first direction and a second polarization of the incident light diffracts in a second direction; an image sensor; and a planar diffractive lens including a second metasurface configured to focus the first polarization of incident light diffracted in the first direction onto a first portion of the image sensor and focus the second polarization of incident light diffracted in the second direction onto a second portion of the image sensor.
1 . A polarization imaging device comprising:
an aperture;
a first metasurface configured to diffract incident light going through the aperture such that a first polarization of incident light diffracts in a first direction and a second polarization of the incident light diffracts in a second direction;
an image sensor;
a planar diffractive lens including a second metasurface configured to focus the first polarization of incident light diffracted in the first direction onto a first portion of the image sensor and focus the second polarization of incident light diffracted in the second direction onto a second portion of the image sensor;
a first substrate, wherein the planar diffractive lens is positioned on the first substrate; and
a reflective surface positioned on the first substrate, wherein the backside of the aperture is reflective, and wherein the reflective surface and the shared aperture create a folded optical path configured to fold the diffracted light.
2 . The polarization imaging device of claim 1 , further comprising a bandpass filter positioned between the planar diffractive lens and the image sensor.
3 . The polarization imaging device of claim 1 , wherein the first metasurface is positioned within an opening of the aperture.
4 . The polarization imaging device of claim 1 , wherein the aperture and the first metasurface are positioned on a same surface of a substrate.
5 . The polarization imaging device of claim 4 , wherein the aperture and the first metasurface are positioned on a surface of the substrate closest to the incident light.
6 . The polarization imaging device of claim 4 , wherein the aperture and the first metasurface are positioned on a surface of the substrate opposite to the incident light.
7 . The polarization imaging device of claim 1 , wherein the first metasurface is further configured to pass a zero order light.
8 . The polarization imaging device of claim 7 , wherein the planar diffractive lens is further configured to focus the zero order light onto a third portion of the image sensor.
9 . The polarization imaging device of claim 1 , wherein the first metasurface directs both the zero order light and the second polarization of the incident light in the same direction.
10 . The polarization imaging device of claim 9 , wherein the planar diffractive lens focuses both the zero order light and the second polarization of the incident light onto the second portion of the image sensor.
11 . The polarization imaging device of claim 9 , wherein the image sensor has a smaller width than the width of the aperture and/or the planar diffractive lens.
12 . The polarization imaging device of claim 1 , wherein the reflective surface and/or the reflective backside of the shared aperture include diffractive structures.
13 . The polarization imaging device of claim 12 , wherein the diffractive structures include metasurface elements.
14 . The polarization imaging device of claim 1 , wherein the aperture and the first metasurface are positioned on a same surface of a second substrate and wherein the folded optical path passes through the second substrate.
15 . The polarization imaging device of claim 1 , wherein the reflective surface is positioned to cover a portion of the first substrate, the planar diffractive lens surrounds the reflective surface, and the diffracted light reflects off the reflective surface, reflects off the reflective backside of the aperture and diffracts through the planar diffractive lens.