A system and method for surface inspection of an object using optical coherence tomography (OCT) is provided. The method includes determining a first working distance; determining a first depth of field, based on the first working distance; changing the depth of field to the first depth of field; performing an A-scan of the object; moving the object; determining a subsequent working distance; determining whether the object is in focus at the subsequent working distance, if the object is not in focus: determining a subsequent depth of field based on the subsequent working distance; changing the depth of field to the first depth of field; and performing an A-scan of the object; and otherwise, performing an A-scan of the object.

Methods and systems for focusing and measuring by mean of an interferometer device, having an optical coherence tomography (OCT) focusing system, by separately directing an overlapped measurement and reference wavefront towards a focus sensor and towards an imaging sensor; where a predefined focusing illumination spectrum of the overlapped wavefront is directed towards the focus sensor, and where a predefined measurement illumination spectrum of the overlapped wavefront is directed towards the imaging sensor. Methods and systems for maintaining focus of an interferometer device, having an OCT focusing system, during sample's stage moves.

Exemplary apparatus and method are provided for illuminating a sample. With such exemplary apparatus and/or method, it is possible to, using at least one source arrangement, provide at least one first electro-magnetic radiation. Using an optical system of an optics arrangement, it is possible to receive the first electro-magnetic radiation(s), and modifying the at least one first electro-magnetic radiation to be at least one second electro-magnetic radiation so as to be forwarded to the sample. Further, with the optical system, it is possible to extend the at least one second electro-magnetic radiation into or across the sample for a distance of at least 2 times the Raleigh range of a Gaussian beam when the optics arrangement and the sample are stationary with respect to one another. Additionally, using the optical system, it is possible to control a placement of a focus of the at least one second electro-magnetic radiation on or in the sample.

Methods and systems for focusing and measuring by mean of an interferometer device, having an optical coherence tomography (OCT) focusing system, by separately directing an overlapped measurement and reference wavefront towards a focus sensor and towards an imaging sensor; where a predefined focusing illumination spectrum of the overlapped wavefront is directed towards the focus sensor, and where a predefined measurement illumination spectrum of the overlapped wavefront is directed towards the imaging sensor. Methods and systems for maintaining focus of an interferometer device, having an OCT focusing system, during sample's stage moves.

Exemplary apparatus and method are provided for illuminating a sample. With such exemplary apparatus and/or method, it is possible to, using at least one source arrangement, provide at least one first electro-magnetic radiation. Using an optical system of an optics arrangement, it is possible to receive the first electro-magnetic radiation(s), and modifying the at least one first electro-magnetic radiation to be at least one second electro-magnetic radiation so as to be forwarded to the sample. Further, with the optical system, it is possible to extend the at least one second electro-magnetic radiation into or across the sample for a distance of at least 2 times the Raleigh range of a Gaussian beam when the optics arrangement and the sample are stationary with respect to one another. Additionally, using the optical system, it is possible to control a placement of a focus of the at least one second electro-magnetic radiation on or in the sample.

A system and method for surface inspection of an object using optical coherence tomography (OCT) with anticipatory depth of field adjustment is provided. The method includes determining a present working distance and one or more forward working distances; determining a present depth of field in which the surface of the object is in focus at the location of the present working distance and at as many of the consecutive forward surface locations as determined possible; changing to the present depth of field; performing an A-scan of the object; moving the object such that the scanner head is directed at each of the consecutive forward surface locations determined to be in the present depth of field; and performing an A-scan at each of the consecutive forward surface locations determined to be in the present depth of field.

An interferometric measuring machine includes an exchangeable lens module system for an optical probe. The probe includes a lens body containing the optical apparatus of an interferometer and a lens module containing an objective lens along an object arm of the interferometer that can be exchanged with other lens modules for varying the measuring characteristics of the probe. The lens modules are adapted to accommodate objective lenses having different focal lengths while maintaining a desired optical path length of the object arm of the interferometer.

An arrangement for determining four-dimensional properties of an interface of an object, including a light source includes: a unit for forming photonic jets, a unit for performing large field of view interferometric imaging of the interface and their combination, a unit for passing the light being close to the interface and direct the light to the interface, and an image unit. The arrangement includes a unit for performing phase shifting interferometric imaging of the interface, imaging a unit for receiving light from the interface modulated by e.g. microspheres for forming super-resolution image information by combining light interferometry with the photonic jets, and a processor unit for determining four-dimensional properties of the interface on the basis of the image information formed by the phase shifting interferometric imaging by utilizing effect of the photonic jets. The arrangement also can also include a unit to carry out the measurement using polarized light.

An interferometric measuring machine includes an exchangeable lens module system for an optical probe. The probe includes a lens body containing the optical apparatus of an interferometer and a lens module containing an objective lens along an object arm of the interferometer that can be exchanged with other lens modules for varying the measuring characteristics of the probe. The lens modules are adapted to accommodate objective lenses having different focal lengths while maintaining a desired optical path length of the object arm of the interferometer.

The problem of measuring height properties (for instance, for aspheric optical components) is addressed by systems and methods that employ heterodyne optical interferometry to detect a plurality of interference patterns corresponding to a plurality of orientations of the surface and that determine a height property (such as a mid-spatial frequency spectrum or topography) of the surface from the plurality of interference patterns.