System and method for interference fringe stabilization

Patent metadata

Field	Value
Publication number	US-11815729-B2
Application number	US-202117229852-A
Country	US
Kind code	B2
Filing date	Apr 13, 2021
Priority date	Apr 13, 2021
Publication date	Nov 14, 2023
Grant date	Nov 14, 2023

Abstract

A system includes a diffractive optical element configured to receive a first beam and a second beam interfering with one another to generate a first interference pattern. The diffractive optical element is also configured to forwardly diffract the first beam and the second beam to output a third beam and a fourth beam. The third beam and the fourth beam interfere with one another to generate a second interference pattern. The system also includes a detector configured to detect the second interference pattern.

First claim

What is claimed is:

1. A system, comprising:
a diffractive optical element configured to:
receive a first beam and a second beam at a first side of the diffractive optical element, the first beam and the second beam being configured to interfere with one another to generate a first interference pattern at the first side of the diffractive optical element; and
forwardly diffract the first beam and the second beam to output a third beam and a fourth beam at a second side of the diffractive optical element, the third beam and the fourth beam being configured to interfere with one another to generate a second interference pattern at the second side of the diffractive optical element;

a detector disposed at the second side of the diffractive optical element, and configured to detect the second interference pattern;
a plurality of optical elements configured to guide the first beam and the second beam to the diffractive optical element;
a reconfigurable reflector disposed in an optical path of the first beam and configured to control a wavefront of the first beam while reflecting the first beam; and
a controller coupled with the detector and the reconfigurable reflector,
wherein the detector is configured to generate a signal based on the detected second interference pattern, and
wherein the controller is configured to control the reconfigurable reflector based on the signal received from the detector to stabilize the first interference pattern.

2. The system of claim 1 , wherein the third beam and the fourth beam substantially overlap with one another.

3. The system of claim 1 , wherein the diffractive optical element comprises:
a first grating and a second grating disposed in parallel with one another.

4. The system of claim 3 , wherein the first grating is mounted on a first movable stage, and the second grating is mounted on a second movable stage, and each of the first movable stage and the second movable stage is independently controllable to adjust an orientation of the first grating or the second grating.

5. The system of claim 3 , wherein the first grating and the second grating are polarization selective gratings.

6. The system of claim 3 , wherein the first grating and the second grating include at least one of a surface relief grating, a transmissive polarization volume hologram grating, or a geometric phase polarization grating.

7. The system of claim 3 , wherein the first grating and the second grating are transmissive polarization volume hologram gratings.

8. The system of claim 1 , wherein the diffractive optical element comprises:
a first grating set and a second grating set arranged in parallel with one another,
wherein at least one of the first grating set or the second grating set includes two or more stacked gratings.

9. The system of claim 1 , further comprising a polarizer disposed between the diffractive optical element and the detector.

10. The system of claim 9 , wherein the polarizer is configured to transform the second interference pattern to a third interference pattern, and the detector is configured to detect the second interference pattern through detecting the third interference pattern.

11. The system of claim 10 , wherein the second interference pattern is a polarization interference pattern, and the third interference pattern is an intensity interference pattern.

12. The system of claim 11 , wherein the first interference pattern is an intensity interference pattern, and a periodicity of the third interference pattern is greater than a periodicity of the first interference pattern.

13. The system of claim 11 , wherein the first interference pattern is a polarization interference pattern, and a periodicity of the second interference pattern is greater than a periodicity of the first interference pattern.

14. A method, comprising:
guiding a first beam and a second beam to a diffractive optical element from a first side of the diffractive optical element, the first beam and the second beam being configured to interfere with one another to generate a first interference pattern at the first side of the diffractive optical element;
forwardly diffracting, by the diffractive optical element, the first beam and the second beam to output a third beam and a fourth beam at a second side of the diffractive optical element, the third beam and the fourth beam being configured to interfere with one another to generate a second interference pattern at the second side of the diffractive optical element;
detecting, by a detector disposed at the second side of the diffractive optical element, the second interference pattern, and generating, by the detector, a signal relating to the detected second interference pattern; and
stabilizing the first interference pattern based on the signal relating to the detected second interference pattern received from the detector,
wherein guiding the first beam and the second beam to the diffractive optical element further comprises: guiding, by a plurality of optical elements, the first beam and the second beam to the diffractive optical element,
wherein stabilizing the first interference pattern based on the signal relating to the detected second interference pattern received from the detector further comprises:
controlling, by a controller, a reconfigurable reflector disposed in an optical path of the first beam based on the signal relating to the detected second interference pattern received from the detector; and
adjusting, by the reconfigurable reflector, a wavefront of the first beam while reflecting the first beam.

15. The method of claim 14 , wherein the diffractive optical element includes a first grating and a second grating arranged in parallel with one another, and forwardly diffracting, by the diffractive optical element, the first beam and the second beam to output the third beam and the fourth beam comprises:
forwardly diffracting, by the first grating, the first beam as a fifth beam propagating toward the second grating;
forwardly diffracting, by the first grating, the second beam as a sixth beam propagating toward the second grating;
forwardly diffracting, by the second grating, the fifth beam as the third beam; and
forwardly diffracting, by the second grating, the sixth beam as the fourth beam,
wherein a first angle formed between the first beam and the second beam is greater than a second angle formed between the third beam and the fourth beam.

16. The method of claim 14 , further comprising:
transforming, by a polarizer disposed between the diffractive optical element and the detector, the second interference pattern to a third interference pattern; and
detecting, by the detector, the second interference pattern through detecting the third interference pattern.

17. The method of claim 14 , wherein the first interference pattern is a polarization interference pattern, the second interference pattern is a polarization interference pattern, and a periodicity of the second interference pattern is greater than a periodicity of the first interference pattern.

18. The method of claim 14 , further comprising:
transforming, by a polarizer disposed between the diffractive optical element and the detector, the second interference pattern to a third interference pattern;
wherein the first interference pattern is an intensity interference pattern, the second interference pattern is a polarization interference pattern, and the third interference pattern is an intensity interference pattern, and
wherein a periodicity of the third interference pattern is greater than a p

Assignees

• Meta Platforms Tech Llc

Inventors

• Lee Yun-Han
• Choi Stephen
• Wang Mengfei
• Wang Junren
• Lu Lu
• Curts Kyle Justin

Classifications

• G02B7/003 Primary

  Alignment of optical elements (G02B7/001, G02B7/002 take precedence; for mirrors G02B7/1822) · CPC title

• G02B5/1823

  in an overlapping or superposed manner · CPC title

• G02B5/32

  Holograms used as optical elements · 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

• G02B27/4233

  having a diffractive element [DOE] contributing to a non-imaging application (diffusers having a diffractive element G02B5/0252; filters having a diffractive element G02B5/203; systems for controlling the direction of light having diffractive elements G02B26/0808; scanning systems having diffractive elements G02B26/106; beam shaping systems using diffractive optical elements G02B27/0944; beam splitting or combining systems operating by diffraction G02B27/1086) · CPC title