Granted Patent B2

US 12,416,752 · App. 18/528,721 · Granted Sep 16, 2025

Inventors: Noah A. Rubin (Cambridge, MA); Federico Capasso (Cambridge, MA)

Assignee: PRESIDENT AND FELLOWS OF HARVARD COLLEGE

G02B5/3025G01J4/04

Abstract

Claims (26)

1. A detector comprising:

a substrate; and

an array of pillars disposed on the substrate, wherein each pillar includes two perpendicular mirror symmetry axes, and each adjacent pair of the pillars are separated by less than 1 micron,

wherein the array of pillars are configured to produce, when illuminated with a polarized incident light, a diffracted light beam with a distinct polarization state for each of a finite number of diffraction orders, wherein the finite number is 2 or more.

2. The detector of claim 1 , wherein the phase-shifting elements comprise titanium dioxide, silicon nitride, an oxide, a nitride, a sulfide, or a pure element.

3. The detector of claim 1 , wherein the array of pillars are further configured to produce, when illuminated with the polarized incident light, four distinct polarization states.

4. The detector of claim 3 , wherein the array of pillars are further configured to produce a +45° linear polarization state, a right circular polarization state, a left circular polarization state and a −45° linear polarization state at −2, −1, +1 and +2 diffraction orders, respectively, when illuminated with the polarized incident light which is +45° linear polarized relative to a surface of the substrate.

5. The detector of claim 3 , wherein the array of pillars are further configured to produce at −2, −1, +1 and +2 diffraction orders four polarization states corresponding to vertices of a tetrahedron inscribed in a Poincaré sphere when illuminated with the polarized incident light which is +45° linear polarized relative to a surface of the substrate.

6. The detector of claim 1 , wherein each dimension of the substrate parallel to a surface of the substrate is no more than 2 millimeters.

7. The detector of claim 1 , wherein polarization states for each of the diffraction orders are linearly independent.

8. The detector of claim 1 , further comprising one or more detecting elements, each configured to detect the diffracted light beam for one of the diffraction orders.

9. The detector of claim 8 , wherein the one or more detecting elements comprise one or more single-wavelength detecting elements, one or more multi-wavelength detecting elements, or one or more imaging sensors.

10. The detector of claim 9 , wherein the one or more single-wavelength detecting elements are linear in intensity at a wavelength of the polarized incident light.

11. The detector of claim 8 , wherein the one or more detecting elements comprises one or more imaging sensor elements.

12. The detector of claim 1 , further comprising a first linear polarizer positioned on an optical path of an incident light towards the array of subwavelength-spaced phase-shifting elements.

13. The detector of claim 12 , further comprising a second linear polarizer on an optical path of the diffracted light beam towards the one or more detecting elements.

14. The detector of claim 13 , wherein an extinction ratio of the second linear polarizer is in a range from 500 to 200,000.

15. The detector of claim 1 , further comprising a refractive lens positioned in an optical path of the diffracted light beam or in an optical path of the incident light.

16. The detector of claim 1 , wherein each of the pillars have different dimensions from at least one other pillar of the array.

17. The detector of claim 16 , wherein the different dimensions comprise different widths or different lengths.

18. The detector of claim 16 , wherein the dimensions of the pillars adjust for independent and tunable phase delays ϕ x and ϕ y on the incident light of x and y polarization.

19. The detector of claim 1 , wherein the array of pillars are rectangular.

20. The detector of claim 1 , wherein the array of pillars tessellate together to form a two-dimensional grating.

21. The detector of claim 1 , wherein the array of pillars all have the same angular orientation.

22. The detector of claim 1 , wherein the array of pillars are formed in unit cells, wherein each unit cell has 10 to 40 pillars.

23. The detector of claim 22 , wherein the unit cells are tessellated to form a two-dimensional grating.

Assignments (1)

Continuity (4)

References Cited (400)

Cited By (4)

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