Easy to use Computer Generated Holograms for Complex Surface Metrology

Author: Dr. Florian Hudelist
Tuesday, June 1, 2021
DIOPTIC GmbH

There are many metrology methods on the market for testing aspheres. The method with one of the highest known accuracies is based on a Fizeau interferometer, in combination with a CGH. We describe a so called DFNL type CGH, having the CGH diffractive structures integrated into the Fizeau reference surface, which provides a solution for measuring complex shapes that is comparable to the traditional methods used for testing spheres. Compared to a standard CGH, the DFNL simplifies the hardware and alignment steps required to measure a complex optical surface.