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US 5,218,471 AGranted
High-efficiency, multilevel, diffractive optical elements
AssigneeMassachusetts Institute of Technology
InventorsGary J. Swanson, Wilfrid B. Veldkamp
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Abstract
The method utilizes high resolution lithography, mask aligning, and reactive ion etching. In particular, at least two binary amplitude masks are generated. A photoresist layer on an optical element substrate is exposed through the first mask and then etched. The process is then repeated for the second and subsequent masks to create a multistep configuration. The resulting optical element is highly efficient.
Claims11
Method for making high-efficiency, multilevel, diffractive optical elements comprising:
- generating at least one binary amplitude mask including multilevel information, the mask being configured to provide 2.sup.N levels where N is the number of masks;
- and
- utilizing the masks' information for constructing 2.sup.N levels in the optical element, the depths of the levels being related by a fixed ratio.
Method for making a high efficiency, multi-level, diffractive optical element comprising:
- providing a substrate including at least two initial levels;
- generating at least one binary amplitude mask including multi-level information;
- and
- utilizing the mask to double the number of levels in the element.
1 more element
Dependencies are inferred from the claim text.