High-efficiency diffractive optical elements Redesign of optical systems thanks to innovative, micro-optical structures
Diffractive optical elements (DOE) diffract light at the microstructured surface. Thanks to their high level of functionality, several optical functions can be integrated simultaneously in a single element. DOEs thus enable very compact, lightweight and elegant practical solutions, which with purely refractive macro optics, are only possible at a very high cost.
High efficiency
The efficiency of a diffractive optical element is enhanced in micro-optics by two factors:
- The individual optics design, which takes into account the optical input conditions and simulates the optical wave propagation through the whole optical system.
- And the continuous surface profile, which is generated by gray-tone lithography with arbitrary step profiles.
Caption: Standard DOE (left) ZEISS DOE (right)
Low zero order
The zero order of a diffractive optical element is reduced at ZEISS by three factors:
- An optimized optics design adapted to the manufacturing tolerances.
- A precise measurement technology that enables the exact determination of the target selectivity (aspect ratio between the structure in the photoresist and the etched structure).
- And a high-precision etching technology that implements the very high requirements for the target selectivity.
Caption: Standard DOE (left) ZEISS DOE (right)
Low roughness
The roughness of a diffractive optical element is reduced by optimizing the entire manufacturing process.
The combination of writing process, development process and etching process at ZEISS delivers precise results with very low roughness. These low-scatter, diffractive, optical elements with sub-nanometer roughness baseline are beneficial in certain applications.
Caption: Standard DOE (left) ZEISS DOE (right)
General specifications
Features |
Parameters |
||
Operating wavelength |
10 nm < λ < 2 μm, EUV to NIR |
||
Materials |
|
||
Substrate surface |
Flat & curved including freeform |
||
Substrate dimensions |
0.5 mm to 300 mm |
||
Substrate thickness |
1 mm to 50 mm |
||
Coating |
Metallic & dielectric |
||
Type |
One- and two-sided structuring |
||
Downloads
-
1
From regular periodic micro-lens arrays to randomized continuous phase profiles, Advanced Optical Technologies, Band 4, Heft 1, Seiten 47–61, eISSN 2192-8584, ISSN 2192-8576, DOI: https://doi.org/10.1515/aot-2014-0062