摘要 |
A method for determining the shape of a rough surface of an object comprises the steps of providing an object having a given roughness related height variation; providing an interferometer for wave front measurement comprising a measurement beam of electromagnetic radiation having a wavelength lambda not exceeding 10 times of the roughness related height variation of the object surface, which measurement beam comprises an incoming wave for illuminating the object surface and an outgoing wave comprising radiation from the incoming wave reflected off the object surface; directing the incoming wave of the measurement beam onto the object surface at least two different probing locations, thereby illuminating an areal element of the object surface at each of the probing locations; and measuring the respective phase distribution of the outgoing wave by means of the interferometer of each of the at least two different probing locations.
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