Achromatic fresnel optics for ultraviolet and x-ray radiation
An achromatic Fresnel optic that combines a Fresnel zone plate and a refractive Fresnel lens. The zone plate provides high resolution for imaging and focusing, while the refractive lens takes advantage of the refraction index change properties of appropriate elements near absorption edges to recombine the electromagnetic radiation of different energies dispersed by the zone plate. This compound lens effectively solves the high chromatic aberration problem of zone plates. The AFO has a wide range of potential applications in lithography, microimaging with various contrast mechanisms and measurement techniques.
1. An EUV and x-ray achromatic lens, comprising:
a combination of a diffractive lens and a refractive Fresnel lens;
wherein said refractive lens is separated from said diffractive lens; and
wherein said diffractive lens comprises a Fresnel zone plate; and
wherein said diffractive lens and said refractive lens are formed on opposite sides of a common substrate and configured to correct chromatic aberration of the lenses.
2. A lens as recited in claim 1 , wherein said diffractive lens comprises a zone plate.
3. A lens as recited in claim 1 , wherein said Fresnel zone plate is selected from the group of Fresnel zone plates consisting essentially of binary zone plates, phase zone plates and blazed zone plates.
4. A lens as recited in claim 1 , wherein aberrations in said achromatic lens are corrected by adjusting geometric parameters of said zone plate.
5. A lens as recited in claim 1 , wherein zones are shifted to less then 2π.
6. A lens as recited in claim 1 , wherein zone positions are computed for specific conjugates to eliminate spherical aberration.
7. A lens as recited in claim 1 , further comprising means for reducing or eliminating coma.
8. A lens as recited in claim 1 , wherein at least a portion of said refractive lens has a stepped face which approximates a desired curvature.
9. A lens as recited in claim 1 , further comprising a plurality of refractive lenses.
10. A lens as recited in claim 1 , further comprising a plurality of diffractive lenses.
11. A lens as recited in claim 1 , wherein said refractive lens has a focal length that crosses zero at a designed operating wavelength.
12. A lens as recited in claim 1 , wherein said refractive lens comprises a material having an absorption edge with in the desired spectral range of the achromatic lens.
13. A lens as recited in claim 12 , wherein said absorption edge comprises a K-edge or an L-edge.
14. A lens as recited in claim 12 , wherein operation of said refractive lens is based on anomalous dispersion of radiation near said absorption edge.
15. An EUV and x-ray achromatic lens, comprising:
a combination of a diffractive lens and a refractive Fresnel lens;
wherein said refractive Fresnel lens is coupled to said diffractive lens;
wherein said diffractive lens comprises a Fresnel zone plate; and
wherein said diffractive lens and said refractive lens are formed on opposite sides of a common substrate and configured to correct chromatic aberration of the lenses.
16. A lens as recited in claim 15 , wherein said diffractive lens and said refractive lens are formed on a common substrate.
17. A lens as recited in claim 15 , wherein said diffractive lens comprises a zone plate.
18. A lens as recited in claim 17 , wherein said Fresnel zone plate is selected from the group of Fresnel zone plates consisting essentially of binary zone plates, phase zone plates and blazed zone plates.
19. A lens as recited in claim 15 , wherein aberrations in said achromatic lens are corrected by adjusting geometric parameters of said zone plate.
20. A lens as recited in claim 15 , wherein zones are shifted to less than 2π.
21. A lens as recited in claim 15 , wherein zone positions are computed for specific conjugates to eliminate spherical aberration.
22. A lens as recited in claim 15 , further comprising means for reducing or eliminating coma.
23. A lens as recited in claim 15 , wherein at least a portion of said refractive lens has a stepped face which approximates a desired curvature.
24. A lens as recited in claim 15 , further comprising a plurality of refractive lenses.
25. A lens as recited in claim 15 , further comprising a plurality of diffractive lenses.
26. A lens as recited in claim 15 , wherein said refractive lens has a focal length that crosses zero at a designed operating wavelength.
27. A lens as recited in claim 15 , wherein said refractive lens comprises a material having an absorption edge with in the desired spectral range of the achromatic lens.
28. A lens as recited in claim 27 , wherein said absorption edge comprises a K-edge or an L-edge.
29. A lens as recited in claim 27 , wherein operation of said refractive lens is based on anomalous dispersion of radiation near said absorption edge.
30. An EUV and x-ray achromatic lens, comprising:
a combination of a Fresnel zone plate and a Fresnel lens;
wherein said Fresnel zone plate comprises a diffractive lens;
wherein said Fresnel lens comprises a refractive lens; and
wherein said diffractive lens and said refractive lens are formed on opposite lenses.
31. A lens as recited in claim 30 , wherein said Fresnel zone plate and said Fresnel lens are formed on a common substrate.
32. A lens as recited in claim 30 , wherein said zone plate is selected from the group of zone plates consisting essentially of binary zone plates, phase zone plates and blazed zone plates.
33. A lens as recited in claim 30 , wherein aberrations in said achromatic lens are corrected by adjusting geometric parameters of said zone plate.
34. A lens as recited in claim 30 , wherein zones are shifted to less than 2π.
35. A lens as recited in claim 30 , wherein zone positions are computed for specific conjugates to eliminate spherical aberration.
36. A lens as recited in claim 30 , wherein said Fresnel lens comprises a refractive Fresnel lens.
37. A lens as recited in claim 30 , further comprising means for reducing or eliminating coma.
38. A lens as recited in claim 30 , wherein at least a portion of said Fresnel lens has a stepped face which approximates a desired curvature.
39. A lens as recited in claim 30 , further comprising a plurality of Fresnel lenses.
40. A lens as recited in claim 30 , further comprising a plurality of diffractive lenses.
41. A lens as recited in claim 30 , wherein said Fresnel lens has a focal length that crosses zero at a designed operating wavelength.
42. A lens as recited in claim 30 , wherein said Fresnel lens comprises a material having an absorption edge with in the desired spectral range of the achromatic lens.
43. A lens as recited in claim 42 , wherein said absorption edge comprises a K-edge or an L-edge.
44. A lens recited in claim 42 , wherein operation of said Fresnel lens is based on anomalous dispersion of radiation near said absorption edge.