Spin-to-orbital angular momentum converter for light

Patent metadata

Field	Value
Publication number	US-2024241288-A1
Application number	US-201816647433-A
Country	US
Kind code	A1
Filing date	Sep 14, 2018
Priority date	Sep 15, 2017
Publication date	Jul 18, 2024
Grant date	—

Abstract

An optical device comprises a metasurface including a plurality of nanostructures. The nanostructures convert an input light of an arbitrary spin state into an output light of an arbitrary total angular momentum state characterized by a superposition of two independent orbital angular momentum (OAM) states.

First claim

What is claimed is:

1 . An optical device, comprising:
a metasurface including a plurality of nanostructures; wherein the nanostructures convert an input light of an arbitrary spin state into an output light of an arbitrary total angular momentum state characterized by a superposition of two independent orbital angular momentum (OAM) states.

2 . The optical device of claim 1 , wherein the input light is a left-circularly or right-circularly polarized light.

3 . The optical device of claim 1 , wherein the output light is a helical beam with independent values of OAM.

4 . The optical device of claim 1 , wherein the input light is of an orthogonal elliptical polarization state.

5 . The optical device of claim 1 , wherein the output light is a superposition of two total angular momentum (TAM) states with independent values of OAM.

6 . A communication device, comprising:
the optical device of claim 1 ; and an encoding device configured to encode information as angular momentums of the output light.

7 . A structured light device, comprising:
the optical device of claim 1 ; and a high numerical aperture lens focusing the output light such that helical modes of the output light have non-trivial field distributions.

8 . The structured light device of claim 7 , wherein the helical modes of the output light carry orbital angular momentum.

9 . A laser device, comprising:
a laser light emitter generating an input light; and the optical device of claim 1 converting the input light into a light carrying an orbital angular momentum.

10 . An optical device, comprising:
a first J-plate configured to convert an incident light state into multiple pure (total angular momentum) TAM states or a superposition of the pure TAM states; and a second J-plate cascaded with the first J-plate and configured to convert the two pure TAM state into multiple design TAM states or a combination of the design TAM states.

11 . The optical device of claim 10 , wherein the second J-plate has an eigen-polarization state different from an eigen-polarization state of the first J-plate.

12 . The optical device of claim 10 , further comprising:
an analyzer including a polarizer configured to filter out linear polarization state.

13 . The optical device of claim 10 , further comprising:
an analyzer including a quarter wave plate and a polarizer configured to filter out circular or elliptical polarization state.

14 . The optical device of claim 10 , wherein the design TAM states include non-separable orbital angular momentum (OAM) states, superposition of two OAM states, superposition of four OAM states, vector vortex beam, or a symmetric rotation patterns from different phase shift in superposition.

15 . The optical device of claim 14 , wherein the spin state of the OAM states depends on an order of the first and second J-plates.

16 . The optical device of claim 10 , wherein an output of the cascaded first and second J-plates depends on an eigen-polarization state of the second J-plates.

17 . The optical device of claim 10 , wherein the first or second J-plate is a spin-to-orbital angular momentum converter.

18 . The optical device of claim 10 , wherein the first or second J-plate transfers orthogonal polarized states to associated conjugate orthogonal polarized state with different OAM states.

19 . The optical device of claim 10 , wherein the design TAM states include non-separable TAM modes or separable TAM modes.

20 . The optical device of claim 19 , wherein the non-separable TAM modes or separable TAM modes are mapped on a cascaded higher-order Poincare sphere (HOPS).

Assignees

• Harvard College

Inventors

• Capasso Federico
• Ambrosio Antonio
• Rubin Noah A
• Devlin Robert C
• Huang Yao-Wei

Classifications

• B82Y20/00

  Nanooptics, e.g. quantum optics or photonic crystals · CPC title

• G02B27/286

  for controlling or changing the state of polarisation, e.g. transforming one polarisation state into another (G02B5/3083 takes precedence; light guide coupling means utilising polarising elements G02B6/34) · CPC title

• G02B1/002 Primary

  made of materials engineered to provide properties not available in nature, e.g. metamaterials · CPC title