Synchronous multi-wavelength interferometric method for measuring aspherical surface profile

To our knowledge, a novel synchronous multi-wavelength interferometric technique is introduced. The aspherical surface profile is measured by focusing a multi-wavelength beam at various positions along the optical axis using a dispersive lens, thereby generating a series of spherical waves with varying curvatures. A comprehensive analysis of the operational mechanism of dispersive lenses in aspherical surface metrology is conducted, culminating in the design principles for their axial focal points. This approach significantly enhances measurement efficiency and accuracy while minimizing mechanical movement errors compared to the conventional annular sub-aperture method. Moreover, the integration of dispersive lenses streamlines system design, reduces the complexity of system modeling, and facilitates the development of a more precise digital twin model for subsequent error correction.