A system for measuring the topography of a surface including a carriage assembly and a base assembly. The carriage assembly comprising a plurality of displacement-measuring probes coupled to a carriage support structure. The base assembly positioned adjacent to the carriage assembly and comprising at least one reference object with an opening sized to receive a test object. At least one of the carriage assembly or the base assembly is configured to translate with respect to the other in at least two directions to enable at least one of the displacement-measuring probes to measure a displacement to a reference surface of the reference object and at least another one of the displacement-measuring probes to measure a displacement to a target surface of the target object whose topography is measured.

The present invention relates to a method and an assembly for chromatic confocal spectral interferometery, in particular also for spectral domain OCT (SD-OCT) using multi-spectral light. A multiple (e.g. two, three, four, etc.) axial splitting of foci in the interferometric object arm is performed using a multifocal (e.g. bifocal, trifocal, quattro-focal, etc.) optical component, forming thereby at least two, three or even several groups of chromatically split foci in the depth direction. The multifocal optical component is made of a diffractive optical element (712) and a Schwarzschild objective (5). At least two, three, four or even more differently colored foci of different groups of foci coincide in at least one confocal point in the object space of the setup. Thus, at least two, three or even more spectral wavelets are formed in the case of optical scanning of an object measurement point and spectral detection in the wavenumber domain, which wavelets are at least slightly spectrally separated from each other. This results in a significant increase in the optical primary data in the wavenumber domain and reduces the trade-off of the chromatic confocal spectral interferometry between axial measurement range and depth resolution. From the detected data, it is possible to calculate tan (alpha) as the quotient of the absolute phase shift delta_phi and the associated wavenumber difference delta_k, the Fourier transform over the spectral data, in order to respectively determine the optical path difference.

A dual-optical displacement sensor system includes a scanner including a first and second scanner head including optical displacement sensors providing a first and second beam having a first optical axis (OA) and a second OA. A computing device or programmed circuit is coupled to receive time versus position data from measurements involving alignment target(s) including at least one knife edge pair including a first and second knife edge oriented in a first plane of the alignment target that is essentially perpendicular to the OAs positioned between the scanner heads for interacting with the beams, and implement at least one equation to analyze the data for determining a degree of alignment of the first and second OA. Using the degree of alignment, an algorithm is for automatic alignment of the OAs or assist instructions for a user alignment of the OAs that provides guiding steps for the user for the alignment.

A dual-optical displacement sensor system includes a scanner including a first and second scanner head including optical displacement sensors providing a first and second beam having a first optical axis (OA) and a second OA. A computing device or programmed circuit is coupled to receive time versus position data from measurements involving alignment target(s) including at least one knife edge pair including a first and second knife edge oriented in a first plane of the alignment target that is essentially perpendicular to the OAs positioned between the scanner heads for interacting with the beams, and implement at least one equation to analyze the data for determining a degree of alignment of the first and second OA. Using the degree of alignment, an algorithm is for automatic alignment of the OAs or assist instructions for a user alignment of the OAs that provides guiding steps for the user for the alignment.

An interferometer system includes a measurement arm comprising a measurement dispersive optical system, a reference arm comprising a bulk diffuser object and a reference dispersive optical system, and an output system. The measurement dispersive optical system is positioned to direct measurement chromatic light towards a target, receive diverging chromatic measurement light from the target, and direct detected measurement light from the received diverging chromatic measurement light towards the output system. The reference dispersive optical system is positioned to direct reference chromatic light towards the bulk diffuser object, receive diverging chromatic reference light from the bulk diffuser object, and direct detected reference light from the received diverging chromatic reference light towards the output system. The output system is configured to determine at least one measured property of the target from the detected measurement light and the detected reference light.

A measurement system includes an optical probe that has a reflective prism structure, an input system, and an output system. The reflective prism structure comprises at least two mirrored surfaces on opposing sides of an axis which extends in a direction towards a target. The input system is positioned to receive and direct source light towards one of the mirrored surfaces which is positioned to reflect the source light towards the target. The output system is positioned to receive and output converging light from reflected light that comprises measurement data related to the target. The reflected light is the source light reflected from the target via the other one of the mirrored surfaces and is without substantial overlap with the source light.

The present invention relayes to a method and an assembly for chromatic confocal spectral interferometery, in particular also for spectral domain OCT (SD-OCT) using multi-spectral light. A multiple (e.g. two, three, four, etc.) axial splitting of foci in the interferometric object arm is performed using a multifocal (e.g. bifocal, trifocal, quattro-focal, etc.) optical component, forming thereby at least two, three or even several groups of chromatically split foci in the depth direction. The multifocal optical component is made of a diffractive optical element (712) and a Schwarzschild objective (5). At least two, three, four or even more differently colored foci of different groups of foci coincide in at least one confocal point in the object space of the setup. Thus, at least two, three or even more spectral wavelets are formed in the case of optical scanning of an object measurement point and spectral detection in the wavenumber domain, which wavelets are at least slightly spectrally separated from each other. This results in a significant increase in the optical primary data in the wavenumber domain and reduces the trade-off of the chromatic confocal spectral interferometry between axial measurement range and depth resolution. From the detected data, it is possible to calculate tan (alpha) as the quotient of the absolute phase shift delta_phi and the associated wavenumber difference delta_k, the Fourier transform over the spectral data, in order to respectively determine the optical path difference.

A measurement system includes an optical probe that has a reflective prism structure, an input system, and an output system. The reflective prism structure comprises at least two mirrored surfaces on opposing sides of an axis which extends in a direction towards a target. The input system is positioned to receive and direct source light towards one of the mirrored surfaces which is positioned to reflect the source light towards the target. The output system is positioned to receive and output converging light from reflected light that comprises measurement data related to the target. The reflected light is the source light reflected from the target via the other one of the mirrored surfaces and is without substantial overlap with the source light.

An interferometer system includes a measurement arm comprising a measurement dispersive optical system, a reference arm comprising a bulk diffuser object and a reference dispersive optical system, and an output system. The measurement dispersive optical system is positioned to direct measurement chromatic light towards a target, receive diverging chromatic measurement light from the target, and direct detected measurement light from the received diverging chromatic measurement light towards the output system. The reference dispersive optical system is positioned to direct reference chromatic light towards the bulk diffuser object, receive diverging chromatic reference light from the bulk diffuser object, and direct detected reference light from the received diverging chromatic reference light towards the output system. The output system is configured to determine at least one measured property of the target from the detected measurement light and the detected reference light.

Apparatus and methods are described for optically analyzing an object having a plurality of layers, without needing to use a reference mirror. Light is generated using an extended broadband light source. The light is directed toward the object, such as to create respective images of the light source on the respective layers of the object. Light that is reflected from a point of the object is gathered into a conjugate point in a detector. The thicknesses of the plurality of layers at the point of the object are determined, by analyzing, within the gathered light, interference between light reflected from the plurality of layers of the object at the point. Other applications are also described.