Diffractive optical elements on non-flat substrates using electron beam lithography
AssigneeCalifornia Institute of Technology
InventorsPaul D. Maker, Richard E. Muller, Daniel W. Wilson
Life of this patent
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Abstract
The present disclosure describes a technique for creating diffraction gratings on curved surfaces with electron beam lithography. The curved surface can act as an optical element to produce flat and aberration-free images in imaging spectrometers. In addition, the fabrication technique can modify the power structure of the grating orders so that there is more energy in the first order than for a typical grating. The inventors noticed that by using electron-beam lithography techniques, a variety of convex gratings that are well-suited to the requirements of imaging spectrometers can be manufactured.
Claims14
An optical grating comprising:
- a curved substrate having a plurality of annular regions;
- and
- at least one region of said plurality of annular regions blazed using electron beam lithography to form a diffraction grating on said curved substrate, each of said at least one region having same blaze angle with respect to a local grating surface normal, such that electron beam lithography produces the diffracting grating with substantially small variations in blaze angle within each of said at least one region,
- wherein each region of said at least one region of blazed surface has two segments, said two segments having different slopes to broaden the second order wavelength response.
An optical grating comprising:
- a curved substrate having a plurality of annular regions;
- and
- at least one region of said plurality of annular regions blazed to form a diffraction grating on said curved substrate, each of said at least one region having the same blaze angle with respect to a local grating surface normal and having substantially small variations in blaze angle within each of said at least one region,
- wherein each region of said at least one region of blazed surface has two segments, said two segments having different slopes to broaden the second order wavelength response.
An optical grating comprising:
- a curved substrate having a plurality of annular regions;
- and
- at least one region of said plurality of annular regions blazed to form a diffraction grating on said curved substrate, each of said at least one region having the same blaze angle with respect to a local grating surface normal with substantially small variations in blaze angle within each of said at least one region,
- wherein each region of said at least one region of blazed surface has two segments, said two segments having different slopes to broaden the second order wavelength response.
An optical grating comprising:
- a curved substrate having a plurality of annular regions;
- and
- at least one region of said plurality of annular regions blazed using electron beam lithography to form a diffraction grating on said curved substrate, each of said at least one region having same blaze angle with respect to a local grating surface normal, such that electron beam lithography produces the diffracting grating with substantially small variations in blaze angle within each of said at least one region,
- wherein each region of said at least one region of blazed surface has a compound profile.
Dependencies are inferred from the claim text.