Reduced loss high efficiency diffractive and associated methods
View Patent ↗A sub-wavelength anti-reflective diffractive structure is incorporated with a base diffractive structure having a small period to form a high efficiency diffractive structure. In the high efficiency diffractive structure, the anti-reflective structure and/or the base diffractive structure are altered from their ideal solo structure to provide both the desired performance and minimize reflections.
1. A diffractive structure, comprising:
a surface on which an integrated diffractive structure is formed in accordance with an integrated diffractive design, the integrated diffractive design being formed from:
a base diffractive design which provides a desired function at a design wavelength;
an anti-reflective diffractive design having a period that is smaller than the design wavelength, wherein a depth of the anti-reflective design is on an order of a depth of the base diffractive design; and
the integrated diffractive design formed by deviating at least one of the base diffractive design and the anti-reflective design from a design for that structure alone.
2. The diffractive structure as claimed in claim 1 , wherein the base diffractive design has a period on the order of the design wavelength.
3. The diffractive structure of as claimed in claim 1 , wherein the base diffractive design includes a one-dimensional array of steps.
4. The diffractive structure as claimed in claim 3 , wherein features of the anti-reflective diffractive design form a one dimensional array parallel to the one dimensional array of steps.
5. The diffractive structure as claimed in claim 3 , wherein features of the anti-reflective diffractive design form a one dimensional array orthogonal to the one dimensional array of steps.
6. The diffractive structure as claimed in claim 1 , wherein features of the anti-reflective diffractive structure form a two dimensional array.
7. The diffractive structure as claimed in claim 1 , wherein deviating includes varying at least one of a depth of the base diffractive design, a depth of the anti-reflective diffractive design, and a period of the anti-reflective diffractive design.
8. The diffractive structure as claimed in claim 1 , wherein the base diffractive design is a splitter.
9. The diffractive structure as claimed in claim 1 , wherein features of the base diffractive design and features of the anti-reflective diffractive design are orthogonal to one another in an elongated dimension.
10. The diffractive structure as claimed in claim 1 , wherein the integrated diffractive structure is on the surface.
11. The diffractive structure as claimed in claim 1 , wherein the integrated diffractive structure is in the surface.
12. A diffractive structure, comprising:
a surface on which an integrated diffractive structure is formed in accordance with an integrated diffractive design, the integrated diffractive design being formed from:
a base diffractive design which provides a desired function at a design wavelength;
an anti-reflective diffractive design having a depth on an order of a depth of the base diffractive design; and
the integrated diffractive design formed by deviating at least one of the base diffractive design and the anti-reflective design from a design for that structure alone.
13. The diffractive structure as claimed in claim 12 , wherein deviating includes varying at least one of a depth of the base diffractive design, a depth of the anti-reflective diffractive design, and a period of the anti-reflective diffractive design.
14. The diffractive structure as claimed in claim 12 , wherein the base diffractive design is a splitter.
15. The diffractive structure as claimed in claim 12 wherein features of the base diffractive design and features of the anti-reflective diffractive design are orthogonal to one another in an elongated dimension.
16. The diffractive structure as claimed in claim 12 , wherein the integrated diffractive structure is on the surface.
17. The diffractive structure as claimed in claim 12 , wherein the integrated diffractive structure is in the surface.