Abstract: A dental optical coherence tomography apparatus for measuring tissue in a stomatognathic region of a living body or an artificial composition in the stomatognathic region as a measured object includes: a variable wavelength light source (15); a light splitting portion (19) that splits light-source light emitted from the variable wavelength light source (15) into reference light (29) and measuring light (28); an interference portion (19) that causes the measuring light (28) and the reference light (29) to interfere with each other, thereby generating interference light; a photodetection portion (41) that measures the interference light; and an arithmetic portion (27b) that generates an image of a measured object (22) by Fourier transforming or inverse Fourier transforming the intensity of the interference light, whose wavelength changes with time, that has been detected by the photodetection portion for each of the wavelengths.

Abstract: An interferometer configured for use in optical coherence domain (OCT) reflectometry systems is disclosed. In the preferred embodiments, efficient routing of light and a balanced detection arrangement provide a high signal to noise ratio. In one set of embodiments, a pair of cascaded 2×2 couplers is used to split light along separate sample and reference paths and also for combining light returning from those paths and supplying the interfered collected light to the detection system. The interferometer can be used with various OCT modalities including time-domain and frequency domain approaches.

Abstract: A superluminescent diode according the present invention employs a unoform AlGaInAs quantum well on an InP substrate, emitting in a range of 1100 to 1800 nm. The favorable conduction band: valence band offset ratio of this material system enables superluminescent diodes which simultaneously provide high power and large optical bandwidth. A recent reduction to practice of the present invention simultaneously demonstrates output power exceeding 100 mW and bandwidth exceeding 100 nm. A preferred embodiment of this invention uses multiple uniform AlGaInAs quantum wells with two confined quantum states and energetic separation in a range of 100-130 nm. An alternate preferred embodiment uses non-uniform wells, with each well having two confined quantum states. The present invention is particularly useful in time domain and spectral domain optical coherence tomography systems, providing increased resolution and tissue penetration for in-vivo imaging.

Abstract: Provided is an optical image measuring apparatus forming a three-dimensional image based on tomographic images of an object, acquired at various depths even when the object moves during measurement. Including a half mirror (6) for dividing a light beam signal light (S) and reference light (R), a frequency shifter (8), a reference mirror (9) and a piezoelectric element (9A) used to change an optical path length of the reference light (R), CCDs (21, 22) for receiving interference light beams (L) resulting from interference light produced by superimposing the signal light (S) and the reference light (R) on each other by the half mirror (6) and outputting detection signals, an image forming portion for forming tomographic images based on the detection signals, a measurement depth calculating means (53), and an image processing portion (57). Forming a three-dimensional image or the like based on the arranged tomographic images.

Abstract: A method determines the complex scattering function of a portion of a sample under analysis. The method includes providing a magnitude spectrum of a complex spatial Fourier transform of a complex intermediate function. The complex intermediate function is dependent on the complex scattering function of the sample. The magnitude spectrum is obtained from power spectrum data of frequency-domain optical coherence tomography of the sample. The method further includes providing an estimated phase term of the complex spatial Fourier transform. The method further includes multiplying the magnitude spectrum and the estimated phase term together to generate an estimated complex spatial Fourier transform. The method further includes calculating an inverse Fourier transform of the estimated complex spatial Fourier transform. The method further includes calculating an estimated intermediate function by applying at least one constraint to the inverse Fourier transform of the estimated complex spatial Fourier transform.

Abstract: An optical coherence tomography system includes an optical source has an emission wavelength in the range of 1.6 ?m to 2.0 ?m, in particular having an infrared emission predominantly at a wavelength of 1.8 ?m associated with a transition between an upper energy level and a lower energy level and the optical source comprises an excitation system which generates stimulated emission from a pump level to the upper energy level. The optical source may include a Tm-doped fiber in an optical cavity.

Abstract: A series of holograms is recorded by synchronizing a camera with laser pulses under the control of a digital delay generator. Amplitude and phase images are calculated while image distances are adjusted for the best focus on the object under observation. The amplitude and phase images are reconstructed while adjusting the image distances over a predetermined range to maintain the object in focus. Numerical superposition of a plurality of holographic fields taken with varying wavelengths provides high resolution microscopic three-dimensional imaging. Numerical reconstruction is based on an angular spectrum method that enables calculation of the image at any distance from the hologram plane. Wavelength scanning digital interference holography also enables image reconstruction along an arbitrarily tilted plane.

Abstract: A method, apparatus and system for optimizing the magnitude of reference levels in non-invasive imaging and analysis is disclosed. Optimizing the magnitude of reference levels enables improving signal to noise ratios and thereby improving the sensitivity and performance of the imaging and analysis system. The invention includes dynamically modifying the magnitude of one or more reference beams and significantly reducing the magnitude of undesirable reference radiation components. It may further include one or more stabilizing feedback systems.

Abstract: Disclosed herein is an apparatus and method for measuring the thickness and profile of a transparent thin film using a white-light interferometer. The apparatus and method separate coherent light according to frequency, obtain a first interference pattern at each frequency, separate composite coherent light according to frequency, and obtain a second interference pattern at each frequency. Further, the apparatus and method obtain a phase, generated by the thickness of the thin film, from the first interference pattern, and acquire only information about the thickness of the thin film. Further, the apparatus and method obtain a phase from the second interference pattern, and acquires information about the profile of the thin film, including information about the thickness of the thin film. Further, by using the thin film thickness information, information about the profile of the thin film is acquired from the thin film profile information including the thin film thickness information.

Abstract: Device for white light interferometry comprising a light source of main emission wavelength ?0 and spectral width ?? and an evaluating unit with a line sensor of pixel width P for detecting an interference fringe pattern with a fringe spacing F, a mask being placed in front of the line sensor having a periodically modulated light transmittance along said line sensor, characterized in that the period length M of the mask is such as to fulfill the condition ? ? ? ? ? 0 < ? 1 - F M ? < 1 2 ? F P - ? ? ? ? ? 0 .

Abstract: A Fourier-domain optical coherence tomography (OCT) imager is presented. An OCT imager according to the present invention can have an auto-alignment process. The auto-alignment process automatically adjusts at least one optical component of a spectrometer of the imager so that the spectrometer is aligned during an imaging session. In addition to the auto-alignment process, OCT spectra are normalized for background spectra and for noise characteristics in order to provide a more accurate and clear OCT image.

Abstract: An accurate measure of eye length can be obtained using concurrent OCT measurements. A position OCT device can be used to continually monitor the position of the front surface of the cornea, while a distance OCT device can determine the apparent distance between the front surface of the cornea and the front surface of the retina. Since the eye is likely to move during the period of time between measurements of the cornea and retina, the monitored position of the cornea can be used to correct the apparent length measurement by the amount of eye movement over that period of time, in order to obtain an accurate measure of eye length.

Abstract: An inner surface measuring apparatus includes: a low coherent light source that outputs low coherent light; a low coherent light dividing section that divides one portion of the low coherent light; a light path length adjusting section that adjusts a light path length of one of the low coherent lights divided by the low coherent light dividing section; a straight rod shaped probe that irradiates the other of the low coherent lights divided from a front end section onto a measurement object; a low coherent light multiplexing section that multiplexes a low coherent light that returns having been reflected on the measurement object with the one low coherent light whose light path length has been adjusted by the light path length adjusting section; a light detector that detects the multiplexed low coherent light; and a rotation mechanism that relatively rotates the probe and the measurement object.

Abstract: A method including: providing a low coherence scanning interferometry data for at least one spatial location of a sample having multiple interfaces, wherein the data is collected using a low coherence scanning interferometer having an illumination geometry and an illumination frequency spectrum, and wherein the data comprises a low coherence scanning interferometry signal having multiple regions of fringe contrast corresponding to the multiple interfaces; and determining a distance between at least one pair of interfaces based on a distance between the corresponding regions of fringe contrast and information about the illumination geometry.

Abstract: A method including comparing information derivable from a scanning interferometry signal for a first surface location of a test object to information corresponding to multiple models of the test object, wherein the multiple models are parameterized by a series of characteristics for the test object. The derivable information being compared may relate to a shape of the scanning interferometry signal for the first surface location of the test object.

Abstract: A half mirror 4 divides a luminous flux emitted from a low-coherence light source 1 into two luminous fluxes, a secondary reference plate 6 is held integrally with a reference plate 16, and a secondary sample 8 is held integrally with a sample 17. A first luminous flux which is obtained through dividing by the half mirror 4 is reflected at a mirror 5 and which reaches a secondary reference surface 6a, is reflected at the secondary reference surface 6a, returns along the same optical path, and is transmitted through the half mirror 4. The second luminous flux reaches a secondary sample surface 8a, is reflected at the secondary sample surface 8a, returns along the same optical path, and is combined with the first luminous flux at the half mirror 4. The optical path length difference between the first luminous flux and the second luminous flux coincides with approximately twice the optical distance between a reference surface 16a and a sample surface 17a.

Abstract: In one embodiment, a system to measure defects on a surface of a wafer and an edge of the wafer using a single tool comprises a radial motor to move an optical head in a radial direction to detect defects at locations displaced from the edge of the wafer, and a rotational motor to rotate the optical head around the edge of the wafer to detect defects on the edge of the wafer.

Abstract: The present invention provides systems, methods and apparatuses that perform digital detection for use in optical tomography. Methods and systems are provided in which digital lock-in detection is performed using an algorithm that employs a phase-independent quadrature technique. Methods and systems are provided in which a unique manipulation of an ordinary averaging filter optimized for sources discrimination and the consequent sampling constraints is presented as a novel filtering scheme for the lock-in detection. Systems and apparatuses are provided which include a digital signal processor which performs digital lock-in detection and an integrated complex programmable logic device for timing control. Apparatuses are provided which include an instrument having an integrated digital signal processor for performing digital processing and detection for use in optical tomography.

Abstract: A tissue imaging system (200) for examining the medical condition of tissue (290) has an illumination optical system (205), which comprises a light source (220), having one or more light emitters, beam shaping optics, and polarizing optics. An optical beamsplitter (260) directs illumination light to an imaging sub-system, containing a spatial light modulator array (300). An objective lens (325) images illumination light from the spatial light modulator array to the tissue. An optical detection system (210) images the spatial light modulator to an optical detector array. A controller (360) drives the spatial light modulator to provide time variable arrangements of on-state pixels. The objective lens operates in a nominally telecentric manner relative to both the spatial light modulator and the tissue. The polarizing optics are independently and iteratively rotated to define variable polarization states relative to the tissue.

Abstract: A method for determining a spatial property of an object includes obtaining a scanning low coherence interference signal from a measurement object that includes two or more interfaces. The scanning low coherence interference signal includes two or more overlapping low coherence interference signals, each of which results from a respective interface. Based on the low coherence interference signal, a spatial property of at least one of the interfaces is determined. In some cases, the determination is based on a subset of the low coherence interference signal rather than on the entirety of the signal. Alternatively, or in addition, the determination can be based on a template, which may be indicative of an instrument response of the interferometer used to obtain the low coherence interference signal.

Abstract: An optical measuring system for detecting geometric data of surfaces of at least one object is described, comprising a beam delivery section, a probe system which is connected to the latter and has a plurality of probe outputs for output of a particular measuring beam to an assigned particular surface location and recording the light reflected back by the surface, and having a downstream analyzer unit for determining the geometric data on the basis of light reflected back by the surface locations. A very accurate and mechanically robust determination of surface geometric data, e.g.

Abstract: A device for the optic measuring of an object (1), including a signal processing unit (2) as well as an interferometer with a light source (3) and with at least one detector (4a, 4d). The interferometer is embodied such that a light beam (12) created by the light source (3) is split at least into a working beam (12a) and a reference beam (12b), with the working beam (12a) impinging the object (1) and the working beam (12a) is at least partially reflected by the object and interfered with the reference beam (12b) on the detector (4a, 4b). The signal processing unit (2) is connected to the detector (4a, 4b) and includes a vibrometer processing unit (2f), which detects the motion of the object (1) from the measuring signals of the detector (4a, 4d).

Abstract: A 4Pi microscope provided with an interferometer wherein two lenses (31, 33) are arranged in such a way that they are opposite to each other on different sides of a sample plane (35); also comprising an optical element (19) which is used to inject illuminating light (3) into the interferometer and/or used to discharge detection light (41) from the interferometer and to deflect a detection beam path, containing a reflecting means (51) which reflects illuminating light discharged by the optical element back into the interferometer and/or which allows detection light which is deflected onto the deflection beam to pass, also reflecting other discharged detection light which is not deflected onto the detection beam path into the interferometer.

Abstract: Methods and related systems for determining properties of optical systems (e.g., interferometers) and/or optical elements (e.g., lenses and/or lens systems) are described. For example, information related to an optical thickness mismatch of an interferometer can be determined by providing scanning interferometry data. The data typically include obtaining one or more interference signals each corresponding to a different spatial location of a test object. A phase is determined for each of multiple frequencies of each interference signal. The information related to the optical thickness mismatch is determined based on the phase for each of the multiple frequencies of the interference signal(s).

Abstract: Methods for employing coherent bundles of optical fibers, whether single- or multi-mode, for optical coherence tomography or optical coherence microscopy. Either a substantially monochromatic source or a broadband source is spatially decohered and/or spatially filtered prior to coupling into the fiber bundle for illumination of a sample. A scatter signal from features disposed beneath the surface of the sample is interfered with a reference signal derived, at either end of the fiber bundle, from the identical source of illumination.

Abstract: A measuring apparatus including a light source that emits light with a wavelength that allows the light to be transmitted through and reflected at each measurement target, a splitter that splits the light from the light source into measurement light and reference light, a reference mirror at which the reference light from the splitter is reflected, a mechanism for driving the reference mirror to adjust the optical path length of the reference light reflected from the reference mirror and a mechanism for measuring the interference of the reference light reflected from the reference mirror as the reference light from the splitter is radiated toward the reference mirror and measurement beams reflected from a plurality of measurement targets as the measurement light from the splitter is radiated toward the measurement targets so as to be transmitted through the measurement targets.

Abstract: A broad band surface profiling apparatus including a reference calibrator for calibrating the apparatus to compensate for surface features of the reference surface. A user is instructed to conduct calibration measurement operations using a calibration sample having a calibration surface to obtain calibration surface topography data for the calibration sample. At each calibration measurement operation, an image representing the calibration surface topography data is displayed to the user and the user has the option to accept or reject the calibration surface topography data represented by the displayed image. The reference calibrator has a surface topography data processor and a mean surface calculator for calculating mean surface topography data using the processed calibration surface topography data accepted by the user to provide reference surface features data.

Abstract: The present invention provides an OCT technique that permits tomographic observation of a biological body parts that is difficult to restrain and also provides a tomographic observation technique for the observation of a constrainable part that does not require constraint and remove the burden from biological body. A wavelength-tunable light generator (wavelength-tunable light source) is employed as the light source of the optical coherence tomography device. The wavelength-tunable light generator has a wave number tunable range width of at least 4.7×10?2 ?m?1 and an emitted-light frequency width of no more than 13 GHz, for example, and includes means capable of changing the wave number stepwise at wave number intervals of no more than 3.1×10?4 ?m?1 and time intervals of no more than 530 ?s.

Abstract: A tunable light source 10 for varying emission wavelength periodically and an optical interferometer are used. A reflector is disposed at a measurement position, a light interference signal is A/D converted at a regular time interval, and data numbers at timing giving peak and bottom are calculated according to a least-squares method. Based on this, an approximate equation is calculated according to polynomial approximation and a sequence including the number of exponentiation of 2 and converting the data number at a regular frequency interval is calculated. Then, by disposing a measured target at the measurement position, calculating the necessary number of pieces of data for FFT from measured data at each timing according to straight-line approximation and Fourier transforming a light beat signal obtained by an optical interferometer at regular frequency interval, a tomogram having high resolution and high sensitivity can be acquired.

Abstract: Common path frequency domain optical coherence reflectometry/tomography devices include a portion of optical fiber with predetermined optical properties adapted for producing two eigen modes of the optical radiation propagating therethrough with a predetermined optical path length difference. The two replicas of the optical radiation outgoing from the portion of the optical fiber are then delivered to an associated sample by an optical fiber probe. The tip of the optical fiber serves as a reference reflector and also serves as a combining element that produces a combination optical radiation by combining an optical radiation returning from the associated sample with a reference optical radiation reflected from the reference reflector. The topology of the devices allows for registering a cross-polarized or a parallel-polarized component of the optical radiation reflected or backscattered from the associated sample.

Abstract: A method and apparatus for analyzing a surface of a test object employs apparatus with a scanning interferometry system which generates a windowed interferometric signal from the surface of a test object to characterize the surface of the test object.

Abstract: Disclosed is a system including: (i) an interferometer configured to direct test electromagnetic radiation to a test surface and reference electromagnetic radiation to a reference surface and subsequently combine the electromagnetic radiation to form an interference pattern, the electromagnetic radiation being derived from a common source; (ii) a multi-element detector; (iii) one or more optics configured to image the interference pattern onto the detector so that different elements of the detector correspond to different illumination angles of the test surface by the test electromagnetic radiation; and (iv) an electronic processor coupled to the detector, wherein the electronic processor is configured to process information measured by the detector to determine information about a test object having the test surface. The measurements made by the detector elements provide ellipsometry/reflectometry data for the test surface.

Abstract: Common path frequency domain optical coherence reflectometry/tomography devices with an additional interferometer are suggested. The additional interferometer offset is adjusted such, that it is ether less than the reference offset, or exceeds the distance from the reference reflector to the distal boundary of the longitudinal range of interest. This adjustment allows for relieving the requirements to the spectral resolution of the frequency domain optical coherence reflectometry/tomography engine and/or speed of the data acquisition and processing system, and eliminates depth ambiguity problems. The new topology allows for including a phase or frequency modulator in an arm of the additional interferometer improving the signal-to-noise ratio of the devices. The modulator is also capable of substantially eliminating mirror ambiguity, DC artifacts, and autocorrelation artifacts. The interference signal is produced either in the interferometer or inside of the optical fiber probe leading to the sample.

Abstract: An integrated interference scanning method, mainly used to integrate the respective advantages of VSI and PSI measurements, hereby achieving the characteristic of high precision and limitless measurement range. In particular, the slope correction factor and the displacement correction factor between the VSI measurement and PSI measurement may be utilized to execute the integration calculation of the height data arrays of the VSI and PSI, so that the scanning procedure may be achieved through merely using the wideband light source of the interference scanning system, as such reducing the errors and complexity of the interference scanning system.

Abstract: An apparatus including an image sensor is disclosed. The apparatus includes a polarization filter, an image sensor, and a processor connected to the image sensor. The polarization filter is adapted to filter out light polarized in a first direction from a first scene. The image sensor is adapted to capture the filtered light, and the image sensor includes support circuits to convert the captured filtered light to image data. The processor is adapted to process the image data to detect features of the first scene. The polarization filter filters out noise component of the image, thus increasing contrast. In another embodiment, a mosaic polarization filter is used to capture a scene in a first image including light from the scene having first polarity and to capture the scene in a second image including light from the scene having first polarity. The two images can be analyzed to determine various characteristics of the scene.

Abstract: A scanningdelay line for use in optical coherence tomography apparatus has a tiltable mirror, and optical convergence means for converging light incident, a dispersive element for dispersing light incident, and an optical-redirector for changing the direction of an icident beam light.

Abstract: Interferometers and autocorrelator based sensors are disclosed that are configured to have multiple sample arms which can be scanned and the backscattered low coherence source light from a sample resolved in a single sweep of one or more variable delays of the sensor. Borescopes and catheters capable of scanning multiple sections or areas of materials and tissues using these sensors are described.

Abstract: A method of measuring the topography of a large, thin, non-flat specular substrate in a production environment with minimal movement of a majority of the measurement apparatus. A gimbal-mounted reflecting element is used to steer a short coherence length probe beam such that the probe beam is substantially perpendicular to a local surface of the substrate. The probe beam and the reference beam are combined and the resulting interference pattern used to characterize defects on the local surface.

Abstract: The invention relates to a method for tomographically displaying a cavity by optical coherence tomography (OCT) and to an OCT device, wherein the path length of a measuring light beam in the catheter can change as a result of a movement of the catheter and brings about a change in the display scale, wherein a possible change in the path length of the measuring light beam in the event of a movement of the catheter is electronically determined and automatically compensated.

Abstract: Apparatus and methods are provided for analyzing surface characteristics of a test object using broadband scanning interferometry. Test objects amenable to these apparatus and methods include but are not limited to semiconductor wafers, semiconductor devices, metallic surfaces, and the like. An interferometry system is used to obtain an interferometry signal and related to data embodied in the signal representative of the test object surface. This signal and/or data is used to construct an n-dimensional function that includes an independent frequency variable and an independent time variable, and/or an n-dimensional function that includes an independent scale variable and an independent time variable, and/or a multi-domain function. These functions are compared with various models to obtain a best match that is then used to characterize the test object surface.

Abstract: An optical imaging system includes an optical radiation source (410, 510), a frequency clock module outputting frequency clock signals (420), an optical interferometer (430), a data acquisition (DAQ) device (440) triggered by the frequency clock signals, and a computer (450) to perform multi-dimensional optical imaging of the samples. The frequency clock signals are processed by software or hardware to produce a record containing frequency-time relationship of the optical radiation source (410, 510) to trigger the sampling process of the DAQ device (440). The system may employ over-sampling and various digital signal processing methods to improve image quality. The system further includes multiple stages of routers (1418, 1425) connecting the light source (1410) with a plurality of interferometers (1420a-1420n) and a DAQ system (1450) triggered by frequency clock signals to perform high-speed multi-channel optical imaging of samples.

Abstract: A metrology apparatus for measuring a parameter of a microscopic structure on a substrate, the apparatus comprising a supercontinuum light source arranged to generate a measurement beam, an optical system arranged to direct the measurement beam onto the substrate and a sensor for detecting radiation reflected and/or diffracted by the structure.

Abstract: An accurate measure of eye length can be obtained using concurrent OCT measurements. A position OCT device can be used to continually monitor the position of the front surface of the cornea, while a distance OCT device can determine the apparent distance between the front surface of the cornea and the front surface of the retina. Since the eye is likely to move during the period of time between measurements of the cornea and retina, the monitored position of the cornea can be used to correct the apparent length measurement by the amount of eye movement over that period of time, in order to obtain an accurate measure of eye length. In some embodiments a single OCT device can serve the dual role of monitoring eye position while making eye length measurements.

Abstract: It is disclosed a method and an apparatus of determining the distance (D) between a collimator lens (13) and an object. Low-coherence light is emitted from a light source (1) and directed the low-coherence light through a collimator lens (13) to the object. The reflected light from the collimator lens (13) and the object is directed to a beam splitter (4) and split into two beams. Within the reference arm the frequency of the beam is shifted by an acousto-optical modulator (5) to a certain frequency and within the delay arm the time delay of the beam is scanned by a variable delay line (7). After combining both beams in a beam combiner (8), the presence of a frequency component equal to the frequency shift of the acousto-optical modulator (5) is detected and the distance (D) between the collimator lens (13) and the object is calculated.

Abstract: An interferometric measuring device for recording the shape, the roughness or the clearance distance of the surface of a measured object is provided, the measuring device having a modulating interferometer, to which is supplied short-coherent radiation by a radiation source, and which has a first beam splitter for splitting the radiation supplied into a first beam component guided via a first arm, and into a second beam component guided via a second arm. One beam is shifted with respect to the other beam, with the aid of a modulating device, in terms of the beam's light phase or light frequency, and passes through a delay line. The two beams are subsequently combined at an additional beam splitter of the modulating interferometer.

Abstract: The invention relates to a method for optical coherence tomography comprising the steps of: providing of a reference light beam and a measurement light beam, combining of the reference light beam and the measurement light beam to provide a combined light beam, modulating of the reference light beam, sampling of the combined light beam to measure an amplitude of an intensity variation for each sampling position, adding of the amplitudes to provide an intensity signal for one picture element.

Abstract: The present invention is an alternative Fourier domain optical coherence system (FD-OCT) and its associated method. The system comprises a swept multi-wavelength laser, an optical interferometer and a multi-channel receiver. By employing a multi-wavelength laser, the sweeping range for each lasing wavelength is substantially reduced as compared to a pure swept single wavelength laser that needs to cover the same overall spectral range. The overall spectral interferogram is divided over the individual channels of the multi-channel receiver and can be re-constructed through processing of the data from each channel detector. In addition to a substantial increase in the speed of each axial scan, the cost of invented FD-OCT system can also be substantially less than that of a pure swept source OCT or a pure spectral domain OCT system.

Abstract: A bi-directional optical transmission system comprises an emitter chip, a detector chip, and an optical fiber. An outgoing beam generated by the emitter chip is coupled into the fiber, which also transmits an incoming beam. The detector and emitter chips are arranged in a side-by-side configuration such that the detector chip receives part of the incoming beam. In one embodiment, a thin-clad edge-emitting laser diode is used to reduce power loss of the incoming beam.

Abstract: A surface profiling apparatus and method. Broadband light is directed along sample and reference paths such that light reflected by a region of a sample surface and light reflected by a reference surface interfere. A mover effects relative movement between the sample and reference surfaces along a scan path. A detector senses a series of light intensity values representing interference fringes produced by the region of the sample surface during the movement. A data processor processes the intensity values as they are received during a measurement operation to produce data indicating the position of a coherence peak, and, after completion of a measurement operation, uses this coherence peak position data to obtain data indicative of the height of the surface region. The data processor includes a correlator for correlating intensity values with a correlation function to provide correlation data to enable the position of a coherence peak to be identified.

Abstract: An interferometric measuring device for measuring the shape or profile of a surface of an object by depth scanning includes a radiation source emitting a short coherent beam, a beam splitter for forming an object beam guided by panorama optics to the object via an object light path and a reference beam guided to a reflecting reference element via a reference light path, and an image pick-up which receives the radiation reflected by the object and the reference element and brought into interference and transmits it to an evaluator for determining the surface shape. An accurate and rapid measurement of surfaces, e.g., in narrow cavities, may be accomplished relatively easily in that a reference surface oriented at an angle to the object surface is formed by the reference element, and the measuring device is configured so that the depth scanning for measuring shape is accomplished by laterally moving the object in relation to the object beam.