Systems and methods for unwrapping a phase map are disclosed. Such systems and methods may include receiving a wrapped phase map associated with an interferometric measurement of a sample including patterned features; removing a tilt from the wrapped phase map; generating a background; detecting features in the wrapped phase, the features in the wrapped phase map corresponding to least some of the patterned features of the sample; replacing phases of the features with the background at corresponding locations in the wrapped phase map; unwrapping the modified wrapped phase map using a global phase-unwrapping; applying local phase-unwrapping to restore the phases of the features; and reapplying the tilt to generate an output unwrapped phase map.

An interferometric distance-measurement device includes a multi-wavelength light source which provides a beam having at least three different wavelengths. An interferometer unit splits the beam into measuring and reference beams. The measuring beam propagates in the direction of a measuring reflector movable along a measuring axis and undergoes a back-reflection, and the reference beam propagates in the direction of a stationary reference reflector and undergoes a back-reflection. The back-reflected measuring and reference beams interfere with each other in an interference beam. A detection unit splits the interference beam such that several phase-shifted partial interference signals result for each wavelength. A signal processing unit determines absolute position information regarding the measuring reflector from the partial interference signals of different wavelengths and an additional coarse position signal.

A stage includes a sample table on which a sample is placed, a first drive mechanism moving the sample table in a first direction; a position measurement element measuring a position in the first direction that is a driving direction of the sample table. The stage also has a scale element having a scale measurement axis that is parallel to a first measurement axis in the first direction based on the position measurement element and is different from the first measurement axis in height, and measuring the position of the sample table in the first direction. A controller calculates the orientation of the sample table by using a measurement value by the position measurement element and a measurement value by the scale element and correcting the Abbe error of the sample table.

Provided is a fixed mirror unit capable of adjusting the inclination of a reflection surface and moving the reflection surface in a direction intersecting with the reflection surface with a simple configuration, an interferometer equipped with the fixed mirror unit, and a Fourier transform spectrophotometer. The fixed mirror unit 8 is provided with a plurality of actuators 83 for axially displacing the mirror 87. By displacing the mirror 87 by different amounts of displacements with the plurality of actuators 83, the angle of the reflection surface 87A can be adjusted, while by displacing the mirror 87 by the same amount of displacement with the plurality of actuators 83, the reflection surface 87A can be moved while keeping the angle of the reflection surface 87A constant. As a result, with a simple configuration, the angle of the reflection surface 87A can be adjusted and the reflection surface 87A can be moved along the axial direction.

Provided is a fixed mirror unit capable of adjusting the inclination of a reflection surface and moving the reflection surface in a direction intersecting with the reflection surface with a simple configuration, an interferometer equipped with the fixed mirror unit, and a Fourier transform spectrophotometer. The fixed mirror unit 8 is provided with a plurality of actuators 83 for axially displacing the mirror 87. By displacing the mirror 87 by different amounts of displacements with the plurality of actuators 83, the angle of the reflection surface 87A can be adjusted, while by displacing the mirror 87 by the same amount of displacement with the plurality of actuators 83, the reflection surface 87A can be moved while keeping the angle of the reflection surface 87A constant. As a result, with a simple configuration, the angle of the reflection surface 87A can be adjusted and the reflection surface 87A can be moved along the axial direction.

A stage includes a sample table on which a sample is placed, a first drive mechanism moving the sample table in a first direction; a position measurement element measuring a position in the first direction that is a driving direction of the sample table. The stage also has a scale element having a scale measurement axis that is parallel to a first measurement axis in the first direction based on the position measurement element and is different from the first measurement axis in height, and measuring the position of the sample table in the first direction. A controller calculates the orientation of the sample table by using a measurement value by the position measurement element and a measurement value by the scale element and correcting the Abbe error of the sample table.

An optical sensor in which an optical component more inexpensive than a corner cube is used as a measurement target and which has accuracy similar to that of a case where the corner cube is used is provided. An optical sensor 1 includes a light source 2, a dividing unit 6, a retroreflection unit 4 that retroreflects first light and second light divided by the dividing unit 6, a combining unit 7, a light receiving unit 5, and a calculation unit 8. The retroreflection unit 4 includes a first retroreflector 4a that retroreflects the first light in parallel in an opposite direction of an incident direction of the first light by performing reflection thereof twice, a second retroreflector 4b that retroreflects the second light in parallel in an opposite direction of an incident direction of the second light by performing reflection thereof twice, and a third retroreflector 4c that retroreflects the first light, which is emitted from the first retroreflector 4a, to the first retroreflector 4a and retroreflects the second light, which is emitted from the second retroreflector 4b, to the second retroreflector 4b.

Various systems and methods for sequential angle illumination to achieve ultra-high resolution optical coherence tomography (OCT) images. One example OCT system includes a light source, a beam divider, sample arm optics, a detector, and a processor. The light source generates a light beam to illuminate the sample. The beam divider separates the light beam into reference and sample arms. The sample arm optics sequentially illuminates a location in the sample with the light beam from different angles. The detector receives light returned from the reference arm and the sample illuminated at each angle and generates signals. The processor combines the signals to generate an image, which has a transverse resolution that is higher than the transverse resolution achieved from the signal generated from a single angle.

A light measurement device that maintains high measurement precision. The light measurement device includes: light source that irradiates light upon measurement object; branch part that splits transmitted light or reflected light from measurement object; phase-changing unit that changes the phase of one beam of the branched light beams; phase-fixing unit that maintains the phase of the other beam of the branched light beams; adjustment mechanism, which is provided in phase-changing unit or phase-fixing unit, for adjusting the propagation direction of light; multiplexer that causes the light emitted by each of phase-changing unit and phase-fixing unit to interfere with each other; detection unit that detects light that is interfered with by multiplexer; and control unit that controls the adjustment mechanism on the basis of the luminance values of an interference image that is detected by detection unit and adjusts the propagation direction of light in phase-changing unit or phase-fixing unit.

An interferometric distance-measurement device includes a multi-wavelength light source which provides a beam having at least three different wavelengths. An interferometer unit splits the beam into measuring and reference beams. The measuring beam propagates in the direction of a measuring reflector movable along a measuring axis and undergoes a back-reflection, and the reference beam propagates in the direction of a stationary reference reflector and undergoes a back-reflection. The back-reflected measuring and reference beams interfere with each other in an interference beam. A detection unit splits the interference beam such that several phase-shifted partial interference signals result for each wavelength. A signal processing unit determines absolute position information regarding the measuring reflector from the partial interference signals of different wavelengths and an additional coarse position signal.