High-efficiency diffractive optical elements

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.
   

The zero order of a diffractive optical element is reduced at ZEISS by three factors:

1. An optimized optics design adapted to the manufacturing tolerances.
2. 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).
3. And a high-precision etching technology that implements the very high requirements for the target selectivity.

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 output roughness are targeted and beneficial in certain applications.