There is a saying that a system can only be built to a specification to the extent that it can be measured precisely for manufacturing defects. As manufacturing capability has advanced, the need to measure components to very tight precision has required new technologies. Interferometers are systems that use the interference of optical waves to measure very small displacements, often the figure of an optical surface. Interferometric optical systems have two optical paths, a reference arm and a test arm. The reference arm provides a highly accurate reference surface to which a surface under test is compared. The reflected wavefronts from these surfaces interfere at a sensor and provide a fringe pattern that is indicative of the differences.
Quadoa simplifies the modeling of interferometers in a few ways. The object-based optical model allows intuitive setup of components in relative or absolute coordinates. Multi-sequential raytracing separates the optical system definition from the raytrace sequence through the system. Combining the two accelerates system setup and simplifies modeling. There is no need for coordinate shifting surfaces or multi-configurations ignoring components to simulate multiple optical paths.