Robustness Analysis and Optimization of Grating Setups

Gratings are a fundamental tool in the arsenal of many optical engineers, since their physical properties (of diffracting incident light into a set of discrete orders) make them a very attractive tool in many different configurations and for many different applications. It is then of major interest to investigate how well a given grating setup can tolerate small deviations from the design parameters, created by e.g. manufacturing processes. Please take a look at the documents below to find an example in which we optimized a slanted grating to be resistant against variations in its fill factor. We achieved this using the newly released Parameter Variation Analyzer to perform a tolerance analysis of the setup and calculate a merit function that averages the efficiency of the working order for different fill factors.

But the parameters of the grating itself are not the only thing which can influence performance in this kind of system: most periodic structures with small feature sizes are known to be strongly sensitive to the polarization state of incident light. As the second use case for this week, we have selected a scenario in which the polarization dependency of a binary grating is analyzed, and the structure is optimized to perform well under incident light with arbitrary polarization angles.