Patent ID: 7583389

Claim:
A system for determining at least one geometric characteristic of an object, the system comprising: a structure having a reference surface with a known curvature; a stage adapted to hold an object; and an interferometer, comprising: a light source adapted to generate light having a broad spectral bandwidth, a detector; a mirror; a beamsplitter adapted to receive the light from the light source and to divide the light into a first portion and a second portion; wherein the system is configured to provide the first portion of the light from the beamsplitter to illuminate the object and the reference surface, and to provide at least some of the first portion of the light from the object and the reference surface to the detector, and wherein the system is configured to provide the second portion of the light from the beamsplitter to illuminate the mirror, and to provide at least some of the second portion of the light from the mirror to the detector; and means for adjusting an optical path length traveled by the second portion of the light from the beamsplitter to the detector, wherein the detector is adapted to output a signal indicating when an optical path length traveled by the first portion of the light from the beamsplitter to the detector is the same as the optical path length traveled by the second portion of the light from the beamsplitter to the detector.