Advanced Metrology for Atypical Optical Surfaces

Atypical optical surfaces such as conformal optics cannot be tested by current flexible metrology systems because of their problematically large numerical apertures and/or clear apertures (often convex) and/or their large deviations from a best-fitreference (either spherical or cylindrical). Subaperture stitching addresses these challenges while retaining flexibility. We propose the development of a metrology system based on stitching that is engineered with an emphasis on testing surfaces ofextreme aspheric (or acylindrical) departure. The project will focus on surfaces that are rotationally symmetric, or off-axis sections of such surfaces, as well as cylinders and toroids. Sub-millimeter lateral resolution and high precision are alsoimportant goals that will be used in the Phase I assessment of a variety of core metrology devices that could be incorporated into our existing stitching platform. For each device, a variety of specialized developments will be considered to extend themeasurable aspheric departure slopes and allow thorough calibration in order to maximize the system's accuracy. The resulting system will deliver unprecedented abilities for the flexible, cost-effective metrology of atypical optical surfaces. Developinga metrology tool for measuring atypical optical surfaces is important for many applications. Ogive domes and other conformal shapes are immediately needed by the Department of Defense for surveillance, target acquisition and guidance systems. Additionalapplications include precision optics for consumer, scientific, and semiconductor products.