Design and construction of large-aperture reflective interferometers

摘要

Phase measuring interferometry is well established as the premier measurement technology in support of optical component fabrication. Commercial instruments are available that provide surface measurements over a range of radii and diameters. However, microlithographic lenses have increased in complexity and scale to the point that most commercial instruments fail to provide adequate surface coverage. Most severe is the ability to measure large diameter, convex surfaces. Anticipating the demands of today's microlithographic lens production, Tropel began design and construction of a new class of phase measuring interferometers in 1990. As a catadioptric design, these instruments feature a large spherical mirror to accomplish their purpose. This paper reviews the optical design of the large aperture reflective interferometer (LARI), and various considerations in their construction.