title: Step-profile measurement by backpropagation of multiple-wavelength optical fields.
abstract: Multiple-wavelength optical fields on a detecting plane of an interferometer are generated from the interference signals detected for an object surface. The generated optical fields are backpropagated along the optical axis. An optical field along the optical axis is reconstructed by summing the backpropagated fields over the multiple wavelengths. The intensity and phase distributions of the reconstructed optical field provide the position of the object surface with an accuracy of a few nanometers.
authors.affiliation: Faculty of Engineering, Niigata University, Niigata-Shi, Japan. osami@eng.niigata-u.ac.jp
authors.forename: Osami
authors.initials: O
authors.lastname: Sasaki
authors.forename: Hisashi
authors.initials: H
authors.lastname: Tai
authors.forename: Takamasa
authors.initials: T
authors.lastname: Suzuki