Modeling interferometers with lens design software: beyond ray-based approaches

There are a variety of aspects of interferometers that can be well-modeled by using rays. For example, ray-based models allow predictions to be made regarding the changes to a measurement when aberrations are introduced into the input wavefront. However, there are other aspects that are more difficult (or impossible) to model well with ray-based approaches. For instance, when a surface under test is not conjugate to the detector, the effects due to diffraction from the edge of the surface cannot be modeled with ray-based approaches. Modern lens design software generally includes tools for modeling beam propagation. These tools can be used to go beyond conventional ray-based modeling of interferometers. In this paper, we demonstrate the utility of these beam propagation tools by modeling various aspects of a point-diffraction interferometer that go beyond solely ray-based approaches.