A method and apparatus including an interferometer is provided for sequentially recording interferometric sectional images at different depths, in particular for analyzing an eye. By use of an interferometer, which includes an optical reference path and an optical sample path, a sample beam scans a measuring region of a sample, in particular of an eye, so as to generate a deep sectional image. The optical and geometric paths in a sample arm and/or reference arm of the interferometer can be switched quickly between two or more positions. The path length of the sample beam and/or of the reference beam is changed by way of a path length switching unit, deep sectional images are generated at least at two different depths of the sample, and the change of the path length in the switching unit takes place by deflection of the beam paths to different geometric paths.

In an OCT apparatus for obtaining a tomogram using optical interference between signal light and reference light, a first distance between a specific image and a coherence gate is obtained from a first tomogram obtained by imaging. The coherence gate is moved by a set moving distance along a predetermined moving direction. The positional relationship between the specific image and the coherence gate is determined based on the position of the specific image in a second tomogram obtained by imaging after movement of the coherence gate and the position of the specific image in the first tomogram.

A phase gradient calculation unit calculates a phase gradient on a plane intersecting an irradiation direction of light corresponding to an optical coherence tomography signal indicating a state of a sample for each of sample points arranged on the plane. A bulk phase error calculation unit integrates, for each of plurality of paths from an origin that is a sample point where a bulk phase error is determined to a destination that is a sample point where the bulk phase error is not determined, the phase gradient for each of the sample points along each of the plurality of corresponding paths to calculate a path specific phase error at the destination, and combines the path specific phase errors among the plurality of corresponding paths to determine the bulk phase error at the destination.

A three-dimensional profiler includes a broadband radiation source. An interferometric system receives the radiation and includes first and second beam splitters, a moving time delay-inducing reflector, and a stationary reflector. The interferometric system creates a time-delayed optical sample radiation source and an optical reference incident radiation source with the first beam splitter. A stationary sample holder receives the optical sample incident radiation. A reference plane receives the optical reference incident radiation. A detector receives an interference signal from reflected or scattered optical sample radiation and reflected or scattered optical reference radiation. A processor extracts an optical path difference between the reference plane and the sample and reconstructs a three-dimensional morphology of the sample.

The present invention relates to an objective (3) for a confocal system (1) of spectral interferometric measurement, comprising: a source hole (14); a second beam splitter (12) having a partially reflective face (12a), a first beam splitter (10) having a face which is configured to form a reference surface (6) and being located between the source hole (14) and the second beam splitter (12); andlenses (11, 13). The first and second beam splitters are positioned in the objective (3) such that an optical distance (d.sub.ref) between the reference surface (6) and the partially reflective surface (12a) is substantially equal to an optical distance (d.sub.m) between the partially reflective surface (12a) and a focal plane of the objective (3).

Some examples refer to a measurement module for a laser processing apparatus in which a first optical path and a second optical path are defined for laser light within a housing. The first optical path has a fixed predefined optical path length. The second optical path is defined between a connection port of the housing and a coupling port and has a variable optical path length adjustable by an optical path length regulator system. An interferometer system includes a measurement module with a first optical path corresponding to a reference arm of the interferometer system and with a second optical path corresponding to an object arm of the interferometer system. An optical path length regulator system is configured for adjusting an optical path length of the second optical path. A laser processing apparatus includes a laser processing module for laser-processing a workpiece using a work beam and a measurement module.