Metrology System for Freeform Optical Systems

This is a Phase I proposal to develop an extremely versatile optical inspection tool to aid in the manufacture and assembly of freeform optical components such as biconics and Zernike surfaces that are not easily inspected with conventional interferometry. This relatively new class of optics can reduce aberrations, improve the optical performance, reduce system size and weight, and thereby lead to more compact, lightweight, lower cost optical telescopes for space and missile interceptor sensors. Since the optical tolerances achieved in the manufacture of such components have an important bearing on the performance capabilities of the system that employ them, instrumentation and techniques for precision metrology are vital for quality assurance. We will examine optical designs employing freeform surfaces and use selected cases to demonstrate the inspection technique for full aperture precision metrology of such components, including alignment, assembly and packaging procedures that are based on the inspection capability. The proposed wavefront sensor comprises a unique combination of digital holographic interferometry, Hartman wavefront sensing, and adaptive optics that results in an extremely flexible tool. The research team includes MetroLaser and Worchester Polytechnic Institute.