Patent ID: 7002694

Claim:
An interferometer system, comprising: a radiation source for emitting radiation of an adjustable frequency; a reference surface; a support for an object providing an object surface; a position-sensitive radiation detector; a disturbing interference surface; a controller; and an integrator; wherein the radiation source, the reference surface, the support and the radiation detector are positioned such that a first portion of the radiation emitted by the radiation source is incident on the reference surface and reflected as a reference wave field therefrom, a second portion of the radiation emitted by the radiation source is directed towards the object surface to generate an object wave field reflected from the object surface, and the reference wave field and the object wave field are superposed to form an interference pattern having a position-dependent intensity distribution on the radiation detector; wherein the disturbing interference surface is positioned such that radiation emitted from the radiation source is incident thereon and that a disturbing wave field reflected from the disturbing interference surface contributes to the position-dependent intensity distribution on the radiation detector; wherein the controller is configured for setting the adjustable frequency of the radiation emitted by the radiation source to a plurality of different frequencies; and wherein the integrator is controlled to perform position-dependent averaging over the different frequencies of the interference patterns formed on the radiation detector to thereby generate an interferogram.