Virtual interferometer based on vector formula of ray tracing

The digital Moiré interferometer technique (DMIT) based on partial compensation principle is an effective approach for aspheric and freeform measurement. Besides a real interferometer, virtual interferometer, as a part of DMIT, plays an important role in the phase-shifting and alignment. The virtual interferometer based on the ray tracing, by creating a light path which is exactly the same with the actual interferometer, can obtain a simulated virtual interferogram for the phaseshifting and alignment. Generally, the ray tracing is simulated by Zemax software. However, due to the limitation of software, a communication delay between Zemax and other modules will influence the efficiency and response time of the whole system. So, how to realize ray tracing in an efficient way is still worth exploring. In this paper, we present a method for tracing ray to improve the efficiency. By using the vector formula of ray tracing, we can improve the calculation accuracy and shorten the calculation time of ray tracing, which can be used in most optical systems. Furthermore, we implement the algorithm of virtual interferometer on the basis of Visual C++, which is the software development platform of DMIT. In this way, we can integrate the virtual interferometer into the software system of DMIT, and then reduce the calling time between modules. Several simulation results are present to validate the feasibility of our method.