In precision optical assembly and adjustment, we often encounter this "awkward" situation: the subsystem under test itself does not possess independent imaging capabilities, the emitted wavefront is extremely cluttered, and the interferometer simply cannot identify valid data. If your work is in the following scenario, you may be familiar with the frustration of this "blind testing."

From classical interferometry to diffraction compensation, from direct measurement to slope derivation, a plethora of technical terms emerge. For decision-makers, choosing the wrong approach not only means wasting millions of dollars in equipment investment but can also potentially drag down the entire R&D cycle. How can we navigate this complex toolbox and find the key to success? In fact, the fundamental principles remain the same. To help you understand more clearly, we've moved beyond a simple list of equipment and, starting from the two intersecting axes of "surface shape to be measured" and "physical measurement dimension," we've outlined a comprehensive and robust logical framework for optical inspection.

In the field of precision optical inspection, computer-generated holograms (CGHs) are hailed as the "standard" for inspecting aspherical and freeform surfaces. However, in practical applications, engineers often face a crucial choice: amplitude-type CGH or phase-type CGH? This is not only a difference in manufacturing process but also relates to the material properties of the test piece and its ability to suppress stray light. Today, Zhixing Optics will provide an in-depth analysis of the core differences between these two types of CGHs.