Patent Number: 7,042,578

Title: Method and apparatus for absolute figure metrology

Abstract: An apparatus including: an interferometer comprising a series of three partially reflective reference surfaces, wherein the interferometer is configured to direct electromagnetic radiation to a test surface along a path through the series of three partially reflective reference surfaces, and direct the electromagnetic radiation reflected from each of the surfaces to form an optical interference pattern on a detector, wherein the interferometer comprises a first reference optic supporting the first reference surface and a second reference optic supporting the second and third reference surfaces, and wherein the second reference optic is configured to adjustably rotate to exchange an order of the second and third reference surfaces along the path relative to the first reference surface.

Inventors: Deck; Leslie L. (Middletown, CT)

Assignee: Zygo Corporation

International Classification: G01B 9/02 (20060101)

Expiration Date: 5/09/02018