An Instrument for Inspecting Aspheric Optical Surfaces and Components

This is a Phase I proposal to develop an extremely versatile optical inspection tool for determining the optical figure of aspheric optical components, such as test objects, aspheric mirrors, segment mirrors, and optical components that are not easily inspected with conventional interferometry. Modern optical design and manufacturing procedures have begun using such components more and more in routine applications to improve optical system capability. Since the optical tolerances achieved in the manufacture of such components have an important bearing on the performance capabilities of the systems that employ them, instrumentation and techniques for precision metrology are vital for quality assurance. Inspection tools required for these types of optical components have lagged the capability to manufacture them. The proposed work will demonstrate a technique for full aperture precision metrology of such optical components and is anticipated to yield instrument designs that incorporate an extremely robust, reliable, and accurate wavefront sensor for precision metrology of a transmitted or reflected wavefront, together with a projection system that covers the full aperture. The proposed wavefront sensor comprises a unique combination of digital holographic interferometry, Hartmann wavefront sensing, and adaptive optics that results in an extremely flexible tool. For the Phase I study, we propose to employ an existing wavefront sensor instrument to accelerate progress towards production of useful experimental data from tests conducted on existing optical elements.