Abstract: Methods, apparatus and systems for testing an optical element are described. One example device for measuring a test optical component includes a pre-conditioning optical module positioned to receive an optical beam from a light source and to produce a beam having a non-collimated beam profile or a freeform wavefront. The device further includes a beam splitter positioned to receive the beam output from the pre-conditioning optical module and to direct a first portion of the beam to a reference arm configured to accommodate a reference optical component, and to direct a second portion of the beam to a test arm configured to accommodate the test optical component. The device also includes a beam combiner positioned to receive the beams from the reference arm and the test arm after reflection or refraction by the reference and the test optical components.

Abstract: This defect inspection device for emitting illumination light onto a moving and rotating sample and inspecting for sample defects by scanning the sample in a spiral shape or concentric circle shapes comprises: an illumination and detection unit comprising an emission optical system and a detection optical system; a rotary stage for rotating the sample; a rectilinear stage for rectilinearly moving the rotary stage; and a controller for controlling the illumination and detection unit, rotary stage, and rectilinear stage. On the linear path of the rectilinear stage are a scanning start position where illumination light is emitted onto the sample and scanning is started and a sample delivery position where movement of the sample to the scanning start position starts.

Abstract: A tomographic imaging system includes a light source, a light irradiation unit that irradiates light to a transparent material composite thin film sample and a reference mirror and acquires an interference signal between light reflected and scattered from the sample and light reflected from the reference mirror, a light measuring unit that measures the interference signal acquired by the light irradiation unit, a light transmission unit that transmits the light output from the light source to the light irradiation unit and transmits the interference signal of the light transmitted from the light irradiation unit to the light measuring unit; and a signal processing apparatus that converts the interference signal of the sample, outputs the converted interference signal as a tomographic image, and monitors the interference signal acquired by the light irradiation unit to modulate intensity and a polarization state of the light input to the light irradiation unit.

Abstract: 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.

Abstract: A system for an aircraft that includes a plurality of zones including: a first fiber optic cable routed through a zone of the plurality of zones. The first fiber optic cable is attached to a landing gear of the aircraft in the zone of the plurality of zones; and a first controller configured to provide a first optical signal to the first fiber optic cable and obtain a first optical response signal from the first fiber optic cable. The first controller is further configured to determine at least one temperature within the zone of the plurality of zones based on the first optical response signal, the first optical signal, and coherent optical frequency domain reflectometry (COFDR).

Abstract: Portable common path shearing interferometry-based holographic microscopy systems. The system includes a light source, a sample holder, a microscope objective lens, a shear plate and an imaging device positioned in a common path shearing interferometry configuration. A housing is configured to receive and hold the shear plate and maintain a position of the shear plate relative to the microscope objective lens.

Abstract: The invention relates to a device, such as a digital holographic microscope, for detecting and processing a first full image of a measurement object, measured with a first offset, wherein an arrangement is provided for generating at least one further full image with at least one offset that differs from the first offset.

Abstract: We describe apparatus for measurement of thickness and topography of slabs of materials employing probes with filters using polarization maintaining fibers.

Abstract: An interferometer detection system, including a beam splitter receiving a collimated light signal and splitting the signal into a first light signal and a second light signal. The system includes a first mirror receiving and reflecting the first light signal along a first path. The system includes a second mirror receiving and reflecting the second light signal along a second path via a transparent material. The system includes a 2D photosensor array configured to receive from the beam splitter the reflected first light signal merged with the reflected second light signal double passing through the transparent material and configured to generate an interference fringe pattern. A non-sinusoidal interference fringe pattern indicates geometrical variation between a wavefront of the reflected first light signal along the first path and a wavefront of the reflected second light signal double passing through the transparent material along the second path.

Abstract: A method for determining whether or not a single use mold is acceptable, comprises providing a closed lens mold (1) comprising two lens mold halves, and having a first and a second optical lens molding surface forming a molding cavity (15) and defining a molding cavity thickness therebetween, providing at least one interferometer (3), each having at least one thickness measurement beam (31), providing a lens mold holder (2), positioning the lens mold (1) such that the thickness measurement beam (31) of the interferometer (3) impinges on the lens mold (1) for measurement of the distance between the two molding surfaces surrounding the molding cavity (15), measuring the thickness profile of the molding cavity (15) with the interferometer (3) on at least three positions of the molding cavity (15) of the lens mold (1), comparing the measured thickness profile with a predetermined thickness profile to determine whether or not the lens mold (1) is acceptable.

Abstract: A method including obtaining a measurement result from a target on a substrate, by using a substrate measurement recipe; determining, by a hardware computer system, a parameter from the measurement result, wherein the parameter characterizes dependence of the measurement result on an optical path length of the target for incident radiation used in the substrate measurement recipe and the determining the parameter includes determining dependence of the measurement result on a relative change of wavelength of the incident radiation; and if the parameter is not within a specified range, adjusting the substrate measurement recipe.

Abstract: A substrate inspection apparatus is disclosed. The substrate inspection apparatus according to the present disclosure may include: a light source configured to radiate laser light onto a coated film that is spread on a region of a substrate; a light detector configured to obtain optical interference data on an interference between reference light, that is generated by the laser light being reflected from a surface of the coated film, and measurement light, that is generated by the laser light penetrating the coated film and being scattered; and a processor configured to derive a thickness of the coated film corresponding to the region, based on the optical interference data.

Abstract: A thickness measurement system may include an illumination source, a beam splitter to split illumination from the illumination source into two beams, a translation stage configured to translate a reference sample along a measurement direction, a first interferometer to generate a first interferogram between a first surface of a test sample and a first surface of the reference sample, and a second interferometer to generate a second interferogram between a second surface of the test sample and a second surface of the reference sample. A thickness measurement system may further include a controller to receive interference signals from the first and second interferometers as the translation stage scans the reference sample, and determine a thickness of the test sample based on the thickness of the reference sample and a distance travelled by the translation stage between peaks of envelopes of the interference signals.

Abstract: An imaging system comprising of a set of cameras, the cameras having a configured relative camera arrangement; and each camera of the set of cameras comprising at least one corrective optical system. The system and method may comprise of multi-camera variations for coordinated alignment in multi-camera variations and/or split-field optical systems.

Abstract: Techniques for removing interferometry signal phase variations caused by distortion and other effects in a multi-layer stack include: providing an electronic processor sample interferometry data acquired for the stack using a low coherence imaging interferometry system; transforming, by the electronic processor, the sample interferometry data to a frequency domain; identifying a non-linear phase variation from the sample interferometry data in the frequency domain, in which the non-linear phase variation is a result of dispersion introduced into a measurement beam by the test sample; and removing the non-linear phase variation from the sample interferometry data thereby producing compensated interferometry data.

Abstract: A combined workpiece holder and calibration profile configuration (CWHACPC) is provided for integration into a surface profile measurement system. The CWHACPC may comprise at least a first calibration profile portion and a workpiece holding portion that holds a workpiece in a stable position during measurement. The first calibration profile portion comprises a plurality of reference surface regions that have known reference surface z heights or z height differences relative to one another. The first calibration profile portion and the workpiece holding portion are configured to fit within a profile scan path range of the surface profile measurement system, such that the surface profile measurement system can acquire measured surface profile data for the first calibration profile portion and the workpiece during a single pass along the profile scan path. The acquired surface profile data for the reference surface regions may be used to indicate and/or correct certain errors.

Abstract: The present subject matter at-least provides an apparatus for characterization of a slab of a material. The apparatus comprises a plurality of frequency-domain optical-coherence tomography (FD-OCT) probes configured for irradiating the slab of material at at-least one location, and detecting radiation reflected from the slab of material or transmitted there-through. Further, a centralized actuation-mechanism is connected to the plurality of OCT probes for simultaneously actuating one or more elements in each of said OCT probes to at-least cause a synchronized detection of the radiation from the slab of material. A spectral-analysis module is provided for analyzing at least an interference pattern with respect to each of said OCT probes to thereby determine at least one of thickness and topography of the slab of the material.

Abstract: A monitoring and deposition control system and method of operation thereof including: a deposition chamber for depositing a material layer on a substrate; a sensor array for monitoring deposition of the material layer for changes in a layer thickness of the material layer during deposition; and a processing unit for adjusting deposition parameters based on the changes in the layer thickness during deposition.

Abstract: Inspecting a multilayer sample. In one example embodiment, a method may include receiving, at a beam splitter, light and splitting the light into first and second portions; combining, at the beam splitter, the first portion of the light after being reflected from a multilayer sample and the second portion of the light after being reflected from a reflector; receiving, at a computer-controlled system for analyzing Fabry-Perot fringes, the combined light and spectrally analyzing the combined light to determine a value of a total power impinging a slit of the system for analyzing Fabry-Perot fringes; determining an optical path difference (OPD); recording an interferogram that plots the value versus the OPD for the OPD; performing the previous acts of the method one or more additional times with a different OPD; and using the interferogram for each of the different OPDs to determine the thicknesses and order of the layers of the multilayer sample.

Abstract: A pattern inspection apparatus includes a first stage to mount an inspection target object, located at the position displaced from the gravity center of the first stage, first and second two-dimensional scales on the first stage and opposite each other with respect to the gravity center, a second stage under a region overlapping with the gravity center of the first stage and not overlapping with the target object, to support and move the first stage, a calculation processing circuitry to calculate the position of the inspection target object, using position information measured by the first and second two-dimensional scales, a sensor to capture an optical image of a pattern on the inspection target object in the state where the first stage on which the inspection target object is mounted is moving, and a comparison unit to compare, for each pixel, the optical image with a corresponding reference image.

Abstract: A fiber optic pressure and mass velocity sensor for measuring a shock wave pressure in a solid media includes an optical fiber having a means for measuring a change in an optical path length (OPL) of the fiber when positioned in the solid media caused by the shock wave altering the physical length of the fiber and the refractive index of the fiber. The means for measuring the change in the OPL is coupled at one end to a laser and at its second end to a means for detecting the change in OPL. The sensor has a high operating bandwidth (>>10 MHz), is sufficiently rigid to withstand the force of the shock wave, has a sensitivity that can also be tailored for the application, and is immune to electromagnetic interference. Measurement can be made on materials under extreme strain conditions, and the sensor can also provide characterization of protective materials such as bullet/blast proof materials.

Abstract: The subject disclosure is directed towards a high resolution, high frame rate, robust stereo depth system. The system provides depth data in varying conditions based upon stereo matching of images, including actively illuminated IR images in some implementations. A clean IR or RGB image may be captured and used with any other captured images in some implementations. Clean IR images may be obtained by using a notch filter to filter out the active illumination pattern. IR stereo cameras, a projector, broad spectrum IR LEDs and one or more other cameras may be incorporated into a single device, which may also include image processing components to internally compute depth data in the device for subsequent output.

Abstract: A system and method for performing a wet etching process is disclosed. The system includes multiple processing stations accessible by a transfer device, including a measuring station to optically measure the thickness of a wafer before and after each etching steps in the process. The system also includes a controller to analyze the thickness measurements in view of a target wafer profile and generate an etch recipe, dynamically and in real time, for each etching step. In addition, the process controller can cause a single wafer wet etching station to etch the wafer according to the generated etching recipes. In addition, the system can, based on the pre and post-etch thickness measurements and target etch profile, generate and/or refine the etch recipes.

Abstract: A polishing method is used for polishing a film formed on a substrate by pressing the substrate against a polishing pad. The polishing method includes preparing, in advance, an algorithm for correction of polishing time from a relationship between a known amount of wear of the polishing pad or a known thickness of the polishing pad, and a polishing time and a polishing amount; setting a polishing target value for the film; and measuring an amount of wear of the polishing pad or a thickness of the polishing pad. The polishing method further includes determining an optimal polishing time for the polishing target value from the measured amount of wear of the polishing pad or the measured thickness of the polishing pad and from the algorithm; and polishing the film for the determined optimal polishing time.

Abstract: Disclosed are improved optical detection systems and methods comprising multiplexed interferometric detection systems and methods for determining a characteristic property of a sample, together with various applications of the disclosed techniques.

Abstract: There is provided an optical tomographic observation device which has a resolving power which is higher than those of a conventional optical tomographic observation device and a confocal microscope by a simple configuration by applying a homodyne phase diversity detection technology and designing so as to satisfy the following formula when ? is a wavelength of a laser light source, ?? is a wavelength half width at half maximum, NA is a numerical aperture of an objective optical element, S is an effective area of a photodetector, and M is a detection magnification of a detection surface relative to a condensing surface. 1 NA 2 ? k 1 0.886 ? ? ?? ? ( NA ? 1 - NA 2 ) ? 0.901 ? S M 2 0.441 ? k 1 ? 0.

Abstract: An inspection apparatus includes an optical image acquisition unit to acquire an optical image of a photomask on which a plurality of figure patterns are formed, a first measurement unit to measure a first positional deviation amount in the horizontal direction at each position on the photomask accompanying deflection of the surface of the photomask generated by supporting the photomask using a support method which is used for acquiring the optical image, a second measurement unit to measure a second positional deviation amount of each of the plurality of figure patterns, by using the optical image, and a difference map generation unit to generate a difference map in which a difference value obtained by subtracting the first positional deviation amount from the second positional deviation amount is used as a map value, with respect to a region on the surface of the photomask.

Abstract: A signal interrogation system comprises an optical coupler to split input laser beam into a first laser beam as a power reference and a second laser beam, the optical coupler being coupled to a first path for the first laser beam and a second path for the second laser beam; an optical circulator disposed in the second path; a bi-directional optical switch disposed in the second path and having on one side a single channel end oriented toward the optical circulator and on another side multiple channel ends with multiple switchable channels; a plurality of optical fibers coupled to the multiple channel ends of the bi-directional optical switch; an interference optical signals path coupled to the optical circulator to receive the interference optical signals from the bi-directional switch; and a balanced photo detector to measure a power difference between the interference optical signals and the power reference.

Abstract: Systems and methods for using white light interferometry to measure undercut of a bi-layer structure are provided. One such method involves performing a first scan of a first bi-layer structure with a microscope using a first scan range, where the microscope is configured for white light interferometry, generating a first interferogram using data from the first scan, performing a second scan of the first bi-layer structure with the microscope using a second scan range, generating a second interferogram using data from the second scan, determining a first distance between features of the first interferogram, determining a second distance between features of the second interferogram, and calculating a width of the undercut based on the first distance and the second distance. One such system involves using the microscope and/or a computer to perform one or more actions of this method.

Abstract: Methods of determining an amount and/or a thickness of residual material in a via based on LL-BSE images of the material are disclosed. Embodiments include etching a plurality of vias through at least one material layer on a wafer; loading the wafer with predetermined measurement parameters in a CD-SEM; acquiring an image of each via of interest using LL-BSE imaging; quantifying grey level values of the images; characterizing residuals of the at least one material layer in each via based on the grey level values; determining an etching success rate based on the characterizing of the residuals; adjusting the etching based on the determining of the etching success rate; and repeating the steps of acquiring, quantifying, characterizing, determining, and adjusting until a desired etching success rate is achieved.

Abstract: A calibration wafer and a method for calibrating an interferometer system are disclosed. The calibration method includes: determining locations of the holes defined in the calibration wafer based on two opposite intensity frame; comparing the locations of the holes against the locations measured utilizing an external measurement device; adjusting a first optical magnification or a second optical magnification at least partially based on the comparison result; defining a distortion map for each of the first and second intensity frames based on the comparison of the locations of the holes; generating an extended distortion map for each of the first and second intensity frames by map fitting the distortion map; and utilizing the extended distortion map for each of the first and second intensity frames to reduce at least one of: a registration error or an optical distortion in a subsequent measurement process.

Abstract: Methods and apparatuses are used for optically measuring by interferometry the thickness (T) of an object (2) such as a slice of semiconductor material. Readings of the object thickness by optical interferometry are carried out, rough thickness values (RTW) are obtained and frequencies, indicating how often the rough thickness values occur, are evaluated. A limited set of adjacent rough thickness values whose frequency integration or summation represents an absolute maximum is identified, and the actual value of the thickness of the object is determined as a function of the rough thickness values belonging to said limited set of values. The rough thickness values can be divided up into classes (C) with corresponding frequencies (F), and in this case, a preponderant group (Gmax) of thickness classes is identified as the above-mentioned limited set of adjacent rough thickness.

Abstract: [Problem to be Solved] To improve the measurement accuracy of an interference measurement device which utilizes interference of light. [Means for Solution] An interference measurement device includes a light source 10 for emitting supercontinuum light (SC light), an optical fiber coupler 11 for splitting the SC light into measurement light and reference light, a dispersion compensation element 12, a drive unit 13 for moving the dispersion compensation element 12, and light-receiving means 14 for measuring an interference waveform produced as a result of interference between the measurement light and the reference light. A measurement object 15 to be measured is an Si substrate having a thickness of 800 ?m. The dispersion compensation element 12 is an Si substrate having a thickness of 780 ?m. Namely, the dispersion compensation element 12 is formed of the same material as that of the measurement object 15 and is 20 ?m thinner than the measurement object 15.

Abstract: An etching monitor device capable of high precision measurement in the presence of a mask region capable of producing interference. The device including an interference optical system which acquires reflected interference light containing three interference component signals, which are due respectively to optical path differences of reflected light between three sets of surfaces. The three interference component signals include a first interference based on an optical path between light reflected off of a mask surface and light reflected off of a top surface of the substrate, a second interference based on an optical path between the light reflected off of the top surface of the substrate and light reflected off of a surface to be etched, and a third interference based on an optical path between the light reflected off of the surface to be etched and the light reflected off of the mask surface.

Abstract: The present invention provides a novel simple, portable, compact and inexpensive approach for interferometric optical thickness measurements that can be easily incorporated into an existing microscope (or other imaging systems) with existing cameras. According to the invention, the interferometric device provides a substantially stable, easy to align common path interferometric geometry, while eliminating a need for controllably changing the optical path of the beam. To this end, the inexpensive and easy to align interferometric device of the invention is configured such that it applies the principles of the interferometric measurements to a sample beam only, being a single input into the interferometric device.

Abstract: A light interference system and a substrate processing apparatus can suppress loss of reflection spectrum. The light interference system 1 includes a light source 10, a coupler 41, multiple collimators 12A and 12B, a collimator 42, a mirror 43, a spectrometer 14, and an operation unit 15. The collimator 42 and the mirror 43 are provided at a side of multiple input terminals except a first input terminal and configured to send reflected lights from multiple output terminals to the multiple output terminals again.

Abstract: Provided are a transparent substrate monitoring apparatus and a transparent substrate monitoring method. The transparent substrate monitoring apparatus includes a light emitting unit emitting light; a double slit disposed on a plane defined in a first direction and a second direction intersecting a propagation direction of incident light and includes a first slit and a second slit spaced apart from each other in the first direction to allow the light to pass therethrough; an optical detection unit measuring an intensity profile or position of an interference pattern formed on a screen plane; and a signal processing unit receiving a signal from the optical detection unit to calculate an optical phase difference or an optical path difference.

Abstract: An optical wall-thickness measuring device for transparent articles. This invention may be practiced with any transparent material, amorphous or crystalline, which has two surfaces in close proximity to each other, and has flat or positively curved shape. As used herein, transparent means clear, translucent or partially transmitting such that a discernible image of the second surface reflection can be formed and detected at some wavelength of electromagnetic radiation.

Abstract: In a thickness measuring system for a bonding layer according to an exemplary embodiment, an optical element changes the wavelength of a first light source to enable at least one second light source propagating through a bonding layer to be incident to an object, wherein the bonding layer has an upper interface and a lower interface that are attached to the object; and an optical image capturing and analysis unit receives a plurality of reflected lights from the upper and the lower interfaces to capture a plurality of interference images of different wavelengths, and analyzes the intensity of the plurality of interference images to compute the thickness information of the bonding layer.

Abstract: A system for inspecting specimens such as semiconductor wafers is provided. The system provides scanning of dual-sided specimens using a diffraction grating that widens and passes nth order (n>0) wave fronts to the specimen surface and a reflective surface for each channel of the light beam. Two channels and two reflective surfaces are preferably employed, and the wavefronts are combined using a second diffraction grating and passed to a camera system having a desired aspect ratio. The system preferably comprises a damping arrangement which filters unwanted acoustic and seismic vibration, including an optics arrangement which scans a first portion of the specimen and a translation or rotation arrangement for translating or rotating the specimen to a position where the optics arrangement can scan the remaining portion(s) of the specimen. The system further includes means for stitching scans together, providing for smaller and less expensive optical elements.

Abstract: Methods and systems for resolving and determining sub-wavelength sized features and stresses by using infrared optical and thermal wavelength probing for holographic or interferometric evaluation and testing for all phases of semiconductor device development and manufacture. Specifically, systems and methods are disclosed for extending the range of optical holographic interferometric inspection for testing and evaluating microelectronic devices and determining the interplay of electromagnetic signals and dynamic stresses to the semiconductor material in which an enhanced imaging method provides continuous and varying magnification of the optical holographic interferometric images over a plurality of interleaved optical pathways of varying optical paths and imaging devices.

Abstract: An etch rate monitor apparatus has a substrate, an optical element and one or more optical detectors mounted to a common substrate with the one or more detectors sandwiched between the substrate and optical element to detect changes in optical interference signal resulting from changes in optical thickness of the optical element. The optical element is made of a material that allows transmission of light of a wavelength of interest. A reference waveform and data waveform can be collected with the apparatus and cross-correlated to determine a thickness change. This abstract is provided to comply with rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

Abstract: A temperature measuring method includes: transmitting a light to a measurement point of an object to be measured, the object being a substrate on which a thin film is formed; measuring a first interference wave caused by a reflected light from a surface of the substrate, and a second interference wave caused by reflected lights from an interface between the substrate and the thin film and from a rear surface of the thin film; calculating an optical path length from the first interference wave to the second interference wave; calculating a film thickness of the thin film; calculating an optical path difference between an optical path length of the substrate and the calculated optical path length; compensating for the optical path length from the first interference wave to the second interference wave; and calculating a temperature of the object at the measurement point.

Abstract: The properties of a surface of an object in presence of thin transparent films are determined by generating a library of model signals and processing a measurement signal via searching the library to evaluate films properties and topography. The library may be reduced with principal component analysis to enhance computation speed. Computation enhancement may also be achieved by removal of the height contributions from the signal leaving only the film contribution in the signal. The film measurement signal is compared to a library of film signals to determine the film parameters of the sample. The library of film signals is produced by processing each full signal in a library to similarly remove the height contributions leaving only the film contributions. Additionally, a post-analysis process may be applied to properly evaluate local topography.

Abstract: A polarization imaging apparatus includes a laser light source and an image pickup element. Object light and reference light each include a first polarized-light component polarized in a first direction and a second polarized-light component polarized in a second direction that is different from the first direction. The image pickup element simultaneously captures an image of an interference pattern including (i) a first interference figure, (ii) a second interference figure, (iii) a third interference figure, and (iv) a fourth interference figure. The polarization imaging apparatus includes a reconstructing section generating respective reconstructed images of the object in regard to the first and second polarized-light components, from the first to fourth interference figures, and a polarized-light-image-calculating section obtaining polarized-light images from the reconstructed images.

Abstract: Systems and methods are provided which derive target characteristics from interferometry images taken at multiple phase differences between target beams and reference beams yielding the interferometry images. The illumination of the target and the reference has a coherence length of less than 30 microns to enable scanning the phase through the coherence length of the illumination. The interferometry images are taken at the pupil plane and/or in the field plane to combine angular and spectroscopic scatterometry data that characterize and correct target topography and enhance the performance of metrology systems.

Abstract: A method for automated in-line determination of the center thickness of an ophthalmic lens including providing an inspection cuvette (2) having an optically transparent bottom (21) and a concave inner surface (210) and containing the lens immersed in a liquid, providing an interferometer having a light source and a focusing probe (30) focusing light coming from the light source to a set position (310) of the lens. Focusing probe (30) also directs light reflected at the boundary between the back surface of the lens and the liquid as well as light reflected at the boundary between the front surface of the lens and the liquid or at the boundary between the front surface of the lens and the concave inner surface (210) to a detector of the interferometer. The center thickness of the lens is determined using the light reflected at the respective boundary at the back surface and at the front surface of the lens.

Abstract: An analyzer comprising a source of electromagnetic radiation, a detector for said radiation and a drophead comprising a surface which is adapted to receive a drop of liquid to be tested, the drophead being positioned in use relative to the source and detector to illuminate a drop received thereon and to cause an interaction in the path of the electromagnetic radiation between the source and detector, characterized in that said surface of said drophead is dimensioned to constrain the drop to adopt a shape which is dominated more by surface tension forces than by gravitational forces.

Abstract: A shape determining device (X) splits the original light beam from a light source (Y) into two light beams, directs the light beams to the front and back surfaces of the object (1) to be determined, and performs optical heterodyne interference using the split light beams at the front and back surfaces of the object (1) to be determined. In the shape determining device (X), each of the split light beams is further split into a main light beam and a subordinate light beam, the subordinate light beam interferes with the main light beam at each of the front and back surfaces before and after the illumination of the object (1) to be determined, the signals after the interference are phase-detected, and the difference between the phases acquired by the phase detection is detected at each of the front and back surfaces of the object (1) to be determined.

Abstract: An apparatus, method and computer program wherein the apparatus includes at least one interferometer where the at least one interferometer is configured to cause interference of an electromagnetic input signal; wherein the at least one interferometer is configured to receive at least one sensor input signal from at least one sensor such that the sensor input signal controls the interference of the electromagnetic input signal by the at least one interferometer; wherein the at least one interferometer is configured to provide a plurality of outputs where each of the plurality of outputs is provided by the at least one interferometer responding to the at least one sensor input signal with a different sensitivity; and at least one detector configured to detect the plurality of outputs of the at least one interferometer and provide a digital output signal indicative of the at least one sensor input signal.