Optical interferometry allows fast and highly accurate measurements. Particularly, phase-shifting interferometry is widely used in industry for evaluation of surfaces and wavefronts. Despite the great development of optical interferometry, many issues are currently in research. For example, improving the robustness for operation in hard conditions and inducing feasible phase references (phase shifts and carriers).
In phase-shifting interferometry, a crucial stage in practice is the generation of phase shifts. The phase shifter is usually a very expensive and delicate device. In our research group, we have proposed an alternative method to induce phase shifts. In general terms, the interferometer is illuminated with a laser point source; then, the source is displaced laterally with respect the optical axis of the interferometer. The following list summarizes some results of our research on this topic.
- Phase-shifting by lateral displacement of the source.
- Generalized phase-shifting algorithm for inhomogeneous phase shifts.