Diffractive optical elements (DOEs) for high tolerance of structured light
Disclosed herein are techniques for structured light pattern generation. A method for generating a one-dimensional structured light pattern in a first direction and with a desired intensity pattern includes generating a plurality of one-dimensional light patterns using a two-dimensional diffractive optical element with different periods in two orthogonal directions, and combining the plurality of one-dimensional light patterns to form the one-dimensional structured light pattern with the desired intensity pattern. Each of the one-dimensional light patterns includes a one-dimensional light pattern in the first direction. The plurality of one-dimensional light patterns is distributed in a second direction different from the first direction. A separation angle between each pair of adjacent one-dimensional light patterns of the plurality of one-dimensional light patterns in the second direction and with respect to the two-dimensional diffractive optical element is less than a threshold value.
1. A method for generating a one-dimensional structured light pattern in a first direction and with a desired intensity pattern, the method comprising:
generating, using a two-dimensional diffractive optical element with different periods in two orthogonal directions, a plurality of one-dimensional diffracted light patterns, wherein:
each of the one-dimensional diffracted light patterns includes a one-dimensional diffracted light pattern in the first direction;
the plurality of one-dimensional diffracted light patterns are distributed in a second direction different from the first direction; and
each pair of adjacent one-dimensional diffracted light patterns of the plurality of one-dimensional diffracted light patterns at least partially overlaps in the second direction at a target plane; and
combining the plurality of one-dimensional diffracted light patterns to form the one-dimensional structured light pattern with the desired intensity pattern.
2. The method of claim 1 , wherein:
a separation angle between each pair of adjacent one-dimensional diffracted light patterns of the plurality of one-dimensional diffracted light patterns in the second direction and with respect to the two-dimensional diffractive optical element is less than a threshold value.
3. The method of claim 2 , wherein:
the separation angle between each pair of adjacent one-dimensional diffracted light patterns of the plurality of one-dimensional diffracted light patterns in the second direction and with respect to the two-dimensional diffractive optical element is less than 0.5 degree.
4. The method of claim 2 , wherein:
the separation angle between each pair of adjacent one-dimensional diffracted light patterns of the plurality of one-dimensional diffracted light patterns in the second direction and with respect to the two-dimensional diffractive optical element is less than 0.2 degree.
5. The method of claim 1 , wherein:
a period of the two-dimensional diffractive optical element in the second direction is at least 40 times of a period of the two-dimensional diffractive optical element in the first direction.
6. The method of claim 1 , wherein:
a period of the two-dimensional diffractive optical element in the second direction is at least 100 times of a period of the two-dimensional diffractive optical element in the first direction.
7. The method of claim 1 , wherein:
the one-dimensional structured light pattern with the desired intensity pattern is a monochromatic light pattern.
8. The method of claim 1 , wherein:
an angle of view of the one-dimensional structured light pattern is greater than 100° in the first direction; and
an angle of view of the one-dimensional structured light pattern is less than 5° in the second direction.
9. The method of claim 1 , wherein:
the desired intensity pattern is a non-uniform pattern.
10. The method of claim 1 , wherein combining the plurality of one-dimensional diffracted light patterns to form the one-dimensional structured light pattern with the desired intensity pattern includes:
combining the plurality of one-dimensional diffracted light patterns using an optical element configured to concentrate light in a direction perpendicular to each of the plurality of one-dimensional diffracted light patterns.
11. An optical device for generating a one-dimensional structured light pattern in a first direction and with a desired intensity pattern, the optical device comprising:
a two-dimensional diffractive optical element configured to generate a plurality of one-dimensional diffracted light patterns, wherein:
each of the one-dimensional diffracted light patterns includes a one-dimensional light pattern in the first direction;
the plurality of one-dimensional diffracted light patterns are distributed in a second direction different from the first direction; and
each pair of adjacent one-dimensional diffracted light patterns of the plurality of one-dimensional diffracted light patterns at least partially overlaps in the second direction at a target plane.
12. The optical device of claim 11 , wherein:
a separation angle between each pair of adjacent one-dimensional diffracted light patterns of the plurality of one-dimensional diffracted light patterns in the second direction and with respect to the two-dimensional diffractive optical element is less than a threshold value.
13. The optical device of claim 12 , wherein:
the separation angle between each pair of adjacent one-dimensional diffracted light patterns of the plurality of one-dimensional diffracted light patterns in the second direction and with respect to the two-dimensional diffractive optical element is less than 0.5 degree.
14. The optical device of claim 12 , wherein:
the separation angle between each pair of adjacent one-dimensional diffracted light patterns of the plurality of one-dimensional diffracted light patterns in the second direction and with respect to the two-dimensional diffractive optical element is less than 0.2 degree.
15. The optical device of claim 11 , wherein:
a period of the two-dimensional diffractive optical element in the second direction is at least 40 times of a period of the two-dimensional diffractive optical element in the first direction.
16. The optical device of claim 11 , wherein:
a period of the two-dimensional diffractive optical element in the second direction is at least 100 times of a period of the two-dimensional diffractive optical element in the first direction.
17. The optical device of claim 11 , wherein:
the two-dimensional diffractive optical element has a multilevel or continuous phase profile in each period.
18. The optical device of claim 11 , further comprising:
an optical element configured to concentrate light in a direction perpendicular to each of the plurality of one-dimensional diffracted light patterns.
19. An optical device for generating a one-dimensional structured light pattern in a first direction and with a desired intensity pattern, the optical device comprising: a two-dimensional diffractive optical element, wherein a period of the two-dimensional diffractive optical element in a second direction is configured such that each pair of adjacent diffraction spots at least partially overlap in the second direction at a target plane, and wherein a period of the two-dimensional diffractive optical element in the first direction is smaller than the period of the two-dimensional diffractive optical element in the second direction.
20. The optical device of claim 19 , wherein:
a separation angle of diffraction spots in the second direction with respect to the optical device is less than 0.5 degree.
21. The optical device of claim 19 , wherein:
a separation angle of the diffraction spots in the second direction with respect to the optical device is less than 0.2 degree.
22. The optical device of claim 19 , wherein:
the period of the two-dimensional diffractive optical element in the second direction is at least 100 times of the period of the two-dimensional diffractive optical element in the first direction.