Disclosed is an optical probe system that is capable of high speed, high precision, and high resolution 3D digitalization of engineered objects. The 3D dimensional data of the engineered object is measured using a swept source optical coherence tomography system with improved speed, spatial resolutions, and depth range. Also disclosed is a type of coordinate measurement machine (CMM) that is capable of performing high speed, high resolution, and non-contact measurement of engineered objects. The mechanic stylus in the touch-trigger probe of a conventional CMM is replaced with an optical stylus with reconfigurable diameter and length. The distance from the center of the optical stylus to the measurement probe is optically adjusted to match the height of the object to be measured quickly, which eliminates one dimensional movement of the probe and greatly improves the productivity.

Apparatus and methods are presented for enhancing the acquisition speed or performance of Fourier domain optical coherence tomography. In preferred embodiments a plurality of wavelength combs containing interleaved selections of wavelengths from a multi-wavelength optical source are generated and projected onto a sample. In certain embodiments the wavelength combs are projected simultaneously onto a plurality of regions of the sample, while in other embodiments the wavelength combs are projected sequentially onto the sample. Light in the wavelength combs reflected or scattered from the sample is detected in a single frame of a sensor array, and the detected light processed to obtain a tomographic profile of the sample. In preferred embodiments the wavelength comb generator comprises a wavelength interleaver in the form of a retro-reflective prism array for imparting different displacements to different selections of wavelengths from the optical source.

Disclosed is an optical probe system that is capable of high speed, high precision, and high resolution 3D digitalization of engineered objects. The 3D dimensional data of the engineered object is measured using a swept source optical coherence tomography system with improved speed, spatial resolutions, and depth range. Also disclosed is a type of coordinate measurement machine (CMM) that is capable of performing high speed, high resolution, and non-contact measurement of engineered objects. The mechanic stylus in the touch-trigger probe of a conventional CMM is replaced with an optical stylus with reconfigurable diameter and length. The distance from the center of the optical stylus to the measurement probe is optically adjusted to match the height of the object to be measured quickly, which eliminates one dimensional movement of the probe and greatly improves the productivity.

Apparatus and methods are presented for enhancing the acquisition speed or performance of Fourier domain optical coherence tomography. In preferred embodiments a plurality of wavelength combs containing interleaved selections of wavelengths from a multi-wavelength optical source are generated and projected onto a sample. In certain embodiments the wavelength combs are projected simultaneously onto a plurality of regions of the sample, while in other embodiments the wavelength combs are projected sequentially onto the sample. Light in the wavelength combs reflected or scattered from the sample is detected in a single frame of a sensor array, and the detected light processed to obtain a tomographic profile of the sample. In preferred embodiments the wavelength comb generator comprises a wavelength interleaver in the form of a retro-reflective prism array for imparting different displacements to different selections of wavelengths from the optical source.

In an OCT imaging, a focus position in a tomographic image is determined by a first distance, a second adjustment amount, a third adjustment amount and a refractive index of a medium. The first distance is a distance between a first surface and a second surface of a wall part of a container. The second adjustment amount is a focus position adjustment amount of an objective optical system at which an intensity of reflected light from the second surface is maximized when a reference mirror is positioned at a position where an object optical path length to the first surface and a reference optical path length are equal in a condition that the objective optical system is focused on the first surface. The third adjustment amount is a focus position adjustment amount in the imaging.

A processing head for a laser processing device adapted for processing a workpiece using laser radiation has: adjustable focusing optics to focus laser radiation in a focal spot having an adjustable distance from the processing head; an optical coherence tomograph to measure a distance between the processing head and the workpiece by measuring an optical interference between measuring light reflected by the workpiece and measuring light not reflected by the workpiece; a path length modulator that can change, synchronously with and dependent on a change of the focal spot distance from the processing head, an optical path length in an optical path along which measuring light propagates; a scanning device, which deflects the laser radiation in different directions; and a control device, which i) controls a focal length of the focusing optics in such a way that the focal spot is situated at a desired location on the workpiece, ii) receives, from the coherence tomograph, information representing the distance between the processing head and the workpiece, and iii) uses information received from the coherence tomograph for a continuous correction of a positioning of the focal spot on the workpiece.

A method for characterising structures etched in a substrate, such as a wafer is disclosed. The method includes, for at least one structure, at least one interferometric measurement step, carried out with a low-coherence interferometer positioned on the top side of the substrate, for measuring with a measurement beam, at least one depth data relating to a depth of said HAR structure, wherein the method also includes a first adjusting step for adjusting a diameter, at the top surface, of the measurement beam according to at least one top-CD data relating to a width of said HAR structure. The invention further relates to a system implementing such a method.

A method for characterising structures etched in a substrate, such as a wafer is disclosed. The method includes at least one structure etched in the substrate, at least one imaging step including the following steps: capturing, with an imaging device positioned on a top side of said substrate, at least one image of a top surface of the substrate, and measuring a first data relating to the structure from at least one captured image, at least one interferometric measurement step, carried out with a low-coherence interferometer positioned on the top side, for measuring with a measurement beam positioned on the structure, at least one depth data relating to a depth of said structure; wherein the method also comprises a first adjusting step for adjusting said measurement beam according to the first data. A system implementing such a method is also disclosed.

A probe with optimized focal depth, working distance and axial light intensity uniformity, including a single-mode fiber for guiding light, a first gradient index fiber for improving light propagation efficiency and regulating mode energy, a large core fiber for generating mode interference field (MIF) and regulating an mode phase difference, a second gradient index fiber and a no-core fiber for magnifying the MIF, and a third gradient index fiber for focusing.

A thickness evaluation method of the cell sheet according to the invention includes tomographically imaging a cell sheet by optical coherence tomography and obtaining a thickness distribution of the cell sheet based on a result of the tomography imaging. A tomographic image corresponding to one cross section of the cell sheet is obtained by tomography imaging while scanning the light in a main scanning direction. The tomography imaging is performed in every time while moving an incident position of the light at a predetermined feed pitch in a sub-scanning direction, thereby a plurality of the tomographic images corresponding to a plurality of cross-sections are obtained. One-dimensional thickness distributions of the cell sheet in the corresponding cross-sections are obtained based on each of the plurality of tomographic images, and a two-dimensional thickness distribution of the cell sheet is obtained by interpolating the one-dimensional thickness distributions.