Abstract: This invention provides an interferometric detection device configured to maintain a temperature of a sensing area to within 20 m° C. of a first target temperature and to maintain a temperature of the medium within 500 m° C. of a second target temperature The device can do so under conditions in which ambient temperature changes from 0.1° C. to 5° C. over 5 minutes.

Abstract: A system and method for microscale measurement and imaging of the group refractive index of a sample. The method utilizes a broadband confocal high-numerical aperture microscope embedded into an interferometer and a spectrometric means, whereby spectral interferograms are analyzed to compute optical path delay of the beam traversing the sample as the sample is translated through the focus of an interrogating light beam. A determination of group refractive index may serve to disambiguate phase ambiguity in a measurement of refractive index at a specified wavelength. Spatial resolution of object characterization in three dimensions is achieved by imaging the object from multiple viewpoints.

Abstract: A measuring method includes measuring a sum of an optical path length of a test object and a first medium in a first container, introducing light into an area that includes the first medium but does not include the test object and measuring the optical path length of the first medium, measuring a sum of the optical path length of the test object and a second medium in a second container, the second medium having a refractive index different from that of the first medium, introducing the light into an area that includes the second medium but does not include the test object and of measuring the optical path length of the second medium, and calculating a refractive index of the test object based on the measured optical path lengths and an actual distance of an optical path for which each optical path length is measured.

Abstract: The invention relates to a method for determining optical properties by measuring intensities on a thin layer, wherein light is irradiated onto a carrier (105) that has said thin layer and that is at least partially transparent. Interferences on the at least one thin layer are measured as the relative intensity of at least one superpositioned wave, optionally using filter arrangements (113, 115, 117) provided for this purpose, whereupon the reflection coefficient(s) and/or the transmission coefficient(s) from the reflection and/or the transmission on the thin layer are determined. Preferably, the intensity of at least two superpositioned waves is measured. The light may be irradiated directly onto the carrier. The invention also relates to a device for determining optical properties by measuring intensities on a thin layer, said device comprising an analysis unit which stores at least one lookup table. The method and the device are preferably used in the area of homeland security.

Abstract: The invention relates to an optical sensor arrangement comprising a measuring optical fiber demonstrating birefringence modifiable as a function of a measurement variable, and to an optical analysis unit having two optical branches implemented as optical fibers forming a Mach-Zehnder interferometer and an optical coupler for bringing together light guided in the two branches, wherein at least one output of the coupler is optically connected to at least one light-sensitive element, and wherein the analysis unit comprises a polarizing beam splitter from which the optical branches originate, wherein the measurement optical fiber is connected upstream of an optical input of the polarizing beam splitter, and wherein a polarization converter is disposed in a course of one of the optical branches. The invention further relates to a detection method that can be performed using said sensor arrangement.

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: Methods and compositions are provided for detecting biomolecular interactions. The use of labels is not required and the methods can be performed in a high-throughput manner. The invention also provides optical devices useful as narrow band filters.

Abstract: A lithographic apparatus comprises an immersion fluid system and an interferometric temperature detection system. The immersion fluid system is configured to provide immersion fluid to an exposure system. The interferometric temperature detection system is configured to measure a temperature of the immersion fluid.

Abstract: Structure profiles from optical interferometric data can be identified by obtaining a plurality of broadband interferometric optical profiles of a structure as a function of structure depth in an axial direction. Each of the plurality of interferometric optical profiles include a reference signal propagated through a reference path and a sample signal reflected from a sample reflector in the axial direction. An axial position corresponding to at least a portion of the structure is selected. Phase variations of the plurality of interferometric optical profiles are determined at the selected axial position. A physical displacement of the structure is identified based on the phase variations at the selected axial position.

Abstract: An optical device suitable for forming a pixel in a video display. The optical device includes a first layer having a first refractive index; a second layer over the first layer, the second layer having a second refractive index less than the first refractive index; and a third layer over the second layer, the third layer having a third refractive index larger than the second refractive index; and a fourth layer that is at least partially optically absorptive, wherein the optical stack and the fourth layer are a first distance from one another when the device is in a first state and are a second distance from one another when the device is in a second state, the first distance different from the second distance.

Abstract: An optical system includes more than two optical interferometers that generate interference phenomena between optical waves to measure a plurality of distances, a plurality of thicknesses, and a plurality of indices of refraction of a sample. An electromagnetic detector receives an output of the optical interferometers to render a magnified image of at least a portion of the sample. A controller reduces or eliminates undesired optical signals through a hierarchical phase unwrapping of the output of the electromagnetic detector.

Abstract: The measuring method includes a step of causing reference light to enter an object placed in a first medium to measure a first transmitted wavefront, a step of causing the reference light to enter the object placed in a second medium to measure a second transmitted wavefront, a step of measuring first and second placement positions where the object is placed in the first and second media, and a calculating step of calculating an internal refractive index distribution of the object by using measurement results of the first and second transmitted wavefronts. The calculating step calculates the internal refractive index distribution from which a shape component of the object is removed by using the measurement results of the first and second transmitted wavefronts, and first and second reference transmitted wavefronts of a reference object to be placed at positions identical to the first and second placement positions.

Abstract: A method for contactless measurement of the density of a porous material, using a measurement of the refractive index of the material by optical coherence tomography. In the optical coherence tomography technique, the optical path corresponding to the crossing of an object made of the material by a light beam used in the technique, is determined, the thickness of the object is determined, the refractive index of the material is determined from the optical path and from the thickness, and the density of the material is determined from the refractive index.

Abstract: In at least one embodiment, the inventive technology relates to in-vessel generation of a material from a solution of interest as part of a processing and/or analysis operation. Preferred embodiments of the in-vessel material generation (e.g., in-vessel solid material generation) include precipitation; in certain embodiments, analysis and/or processing of the solution of interest may include dissolution of the material, perhaps as part of a successive dissolution protocol using solvents of increasing ability to dissolve.

Abstract: To measure a hollow three-dimensional object without contact, this object being translucent or transparent vis-á-vis a visible light, an image of the object is acquired by single-view backlit shadowgraphy, along a viewing axis, by observing this object with visible light, this image comprising at least one luminous line, an equation is established that connects at least one optogeometric parameter of the object to at least one geometric parameter of the luminous line, this geometric parameter is determined, and the optogeometric parameter is determined by means of the equation and the geometric parameter thus determined.

Abstract: A sensing system using a sensing element being constituted by a transparent body sandwiched by first and second reflectors one or each of which is in contact with a specimen, and exhibiting an absorption characteristic varying with the specimen. The first reflector is a partially transparent reflective, and the second reflector is completely reflective, or partially transparent reflective. A light injection unit injects light onto the first reflector, and a light detection unit detects the intensity of light outputted from the sensing element in response to the injection. The light injection unit has a wavelength stabilizing arrangement and injects laser light, or injects light at two wavelengths. In the latter case, the light detection unit detects the intensities of outputted light at the two wavelengths, and a calculation unit obtains the difference between the intensities.

Abstract: Method and apparatus for determining dielectric function of liquid solutions and thereby concentrations of substances in aqueous solution or the volatile/non-volatile nature of the liquid by self-referenced reflection THz spectroscopy. Having the aqueous solution in any container with a window allows irradiating coherent THz radiation with frequencies within the range 0.05-2 THz on the front of the window, and recording both a reference signal reflected from the front of the window and a sample signal reflected from the back of the window in contact with the aqueous solution. From these signals, the complex index of refraction, (I) or the complex reflection coefficient (II), can be calculated. The calculated components are compared with previously determined components from samples with known concentrations, whereby a concentration of the substance in the mixture can be estimated.

Abstract: The invention involves a sensor (100) with a Bragg network fiber including a source (105) and detection system (101), operating at a wavelength of a given study, in addition to a Bragg (6) network fiber (1) linked to said source and said system, with said fiber being a microstructured optic fiber whose sheath (5) includes channels (3) adjacent to the heart (2) of the fiber (1), capable of receiving a product to be analyzed, characterized in that the number of channels (3) adjacent to the heart (2) is between 2 and 5, and that the size of the heart (2) of the fiber (1) is adapted so that an electromagnetic field of a wave guided by the fiber is not confined in the heart (2) of the fiber (1), and the electromagnetic field extends into the channels (3).

Abstract: Disclosed are improved optical detection systems and methods comprising interferometric detection systems, methods for determining a characteristic property of a fluid, methods for calculating a shift between at least two signals, computer program products encoded in a computer readable medium, and computational systems. Also disclosed are label-free, free-solution, and/or real-time measurements of characteristic properties and/or chemical events using the disclosed techniques. Also disclosed are various biosensor applications of the disclosed techniques. This abstract is intended as a scanning tool for purposes of searching in the particular art and is not intended to be limiting of the present invention.

Abstract: In an interferometer system and a method for its operation, the interferometer system includes an interferometer having an interferometer light source whose emitted radiation is able to be split into a measuring arm and a reference arm, an object to be measured being disposed in the measuring arm, and the interferometer delivering interferometer signals as a function of the position of the object to be measured. In addition, a detecting device is provided for detecting fluctuations in the refractive index of the air in the measuring arm and/or reference arm. The detecting device includes a spectrometer unit; the spectrometer unit has at least one spectrometer light source, as well as at least one spectrometer detector unit.

Abstract: While objects travel through an optical cavity, the cavity provides output light that is affected by the objects, causing the output light to have a varying intensity function. The output light is photosensed to obtain sensing results that depend on the varying intensity function. The sensing results are used to distinguish at least one object, such as from its environment or from objects of other types. The objects can, for example, be particles or biological cells, and their optical characteristics, such as refractive index or absorption, can affect the output light, so that information about them is included in the output light. The output light can, for example, have a laterally varying intensity function with peaks whose features change due to the objects. The sensing results can also be used to track objects, together with other information, such as about the speed of a fluid that carries the objects through the cavity.

Abstract: The present invention provides a microscopy method and a microscope, which enable microscopic observation of desired information of a specimen with an extremely high S/N ratio in a short period of time without increasing intensity of a light sources. The method of the invention is characterized in that it comprises: a simultaneous irradiation step of irradiating a specimen with first and second electromagnetic rays having different wave length with the rays overlapping at least partly each other; and a simultaneous irradiation visualization step of visualizing a spatial distribution of a refractive index variation caused by the irradiation of the first electromagnetic ray as a phase contrast image of the second electromagnetic ray having passed through the specimen in the region of the specimen to which the overlapped the first and the second electromagnetic rays are irradiated.

Abstract: An interferometer comprises a source of a light beam, and a beam splitter for splitting the light beam from the source into at least first and second beams. A first (reference) reflector is positioned in the path of the first light beam. A second reflector, comprising a convergent lens and a mirror, is positioned in the path of the second light beam following reflection from a target. At least one detector is provided for detecting fringes formed by interference of the first and second light beams following reflection from the first and second reflectors respectively.

Abstract: A method of analyzing tissue includes inserting a radiation source into tissue, impinging radiation upon the tissue, obtaining a sample signal of the radiation that impinges upon the tissue, and determining a refractive index of the tissue from the sample signal. The method may also include determining at least one other optical property of the tissue. The method may provide for identifying tissue as part of a biopsy method. A device for analyzing tissue may include a low-coherence interferometer and a probe optically coupled to the interferometer, where the probe includes a radiation source.

Abstract: A method and apparatus are provided for monitoring an immersion photolithography process, the method including supplying an immersion fluid having an initial refractive index, performing photolithography using the supplied immersion fluid, recovering the used immersion fluid; and the apparatus including a light source, one or more fluid passageways disposed relative to the light source, and a light detector disposed on an opposite side of the fluid passageways relative to the light source for measuring a refractive index of a fluid in the fluid passageways.

Abstract: This invention provides methods and devices for analyzing interference patterns. The methods include fitting a Gaussian distribution to a cross correlation of two patterns from interferometric analysis of a liquid at a first and second time; identifying a positional shift of the pattern by comparing a selected value of the Gaussian distributions of the pattern at the first and second times; and determining a change in refractive index of the liquid from the positional shift. In another aspect, a method of extending the dynamic range of an interferometric data set is provided that comprises linearizing the data set, for example, using the arcsine function.

Abstract: A refractive index distribution measurement method includes the steps of measuring a first transmission wavefront of a test object by introducing reference light to the test object immersed in a first medium having a first refractive index lower than that of the test object by 0.01 or more, measuring a second transmission wavefront of the test object by introducing the reference light to the test object immersed in a second medium having a second refractive index lower than that of the test object by 0.01 or more and different from the first refractive index, and obtaining a refractive index distribution of the test object based on a measurement result of the first transmission wavefront and a measurement result of the second transmission wavefront.

Abstract: A method and systems for reticle inspection. The method includes coherently illuminating surfaces of an inspection reticle and a reference reticle, applying a Fourier transform to scattered light from the illuminated surfaces, shifting the phase of the transformed light from the reference reticle such that a phase difference between the transformed light from the inspection reticle and the transformed light from the reference reticle is 180 degrees, combining the transformed light as an image subtraction, applying an inverse Fourier transform to the combined light, and detecting the combined light at a detector. An optical path length difference between two optical paths from the illumination source to the detector is less than a coherence length of the illumination source. The image detected by the detector represents a difference in amplitude and phase distributions of the reticles allowing foreign particles, defects, or the like, to be easily distinguished.

Abstract: A multi-channel swept wavelength optical interrogation system and a method are described herein that enable the interrogation of one or more biosensors which for example could be located within the wells of a microplate. In one embodiment, the optical interrogation system comprises: (a) a tunable laser that emits an optical beam which has a predetermined sequence of distinct wavelengths over a predetermined time period; (b) a distribution unit that splits the optical beam into a plurality of interrogation beams; (c) an array of optical interrogation units that receive and direct the interrogation beams towards an array of biosensors; (d) the array of optical interrogation units receive a plurality of reflected interrogation beams from the array of biosensors; (e) a data processing device that receives and processes information associated with the reflected interrogation beams to determine for example whether or not there was a biochemical interaction on anyone of the biosensors.

Abstract: A new and novel sensor having a simple structure with high detection sensitivity. The sensor (S1) includes the following from measuring light (L1) input side in the order listed below: a first reflector (10) having semi-transmissive and semi-reflective properties; a translucent body (20); and a second reflector (30) having perfect reflection properties, or semi-transmissive and semi-reflective properties. The first reflector (10) and/or second reflector is brought into contact with a specimen, and the average complex refractive index varies with the specimen. Absorption properties for absorbing light having a particular wavelength are produced by these components, the properties of the measuring light (L1) are changed by the optical properties including the absorption properties, the output light (L2) is outputted from the first reflector (10) and/or second reflector (30), and the physical properties of the output light (L2) that vary according to the optical properties are detected.

Abstract: A tunable optical cavity can be tuned by relative movement between two reflection surfaces, such as by deforming elastomer spacers connected between mirrors or other light-reflective components that include the reflection surfaces. The optical cavity structure includes an analyte region in its light-transmissive region, and presence of analyte in the analyte region affects output light when the optical cavity is tuned to a set of positions. Electrodes that cause deformation of the spacers can also be used to capacitively sense the distance between them. Control circuitry that provides tuning signals can cause continuous movement across a range of positions, allowing continuous photosensing of analyte-affected output light by a detector.

Abstract: A light branching unit and a reflecting mirror are fixed to a barrel in a state where the distance between the members is constantly maintained. And, a laser beam from a light source is guided to the light branching unit via an optical fiber, separated to a measurement beam and a reference beam by a beam splitter, and a synthesized light of the measurement beam and the reference beam that reciprocate between the light branching unit and the reflecting mirror in the liquid is then guided to a photodetection system via the optical fiber. And, the measurement beam and the reference beam are made to interfere inside this photodetection system, and a change of an optical path length of the measurement beam is measured based on a photoelectric conversion signal of the interference light. Accordingly, change of a refractive index of the liquid can be optically measured.

Abstract: Disclosed is a low-cost high-resolution compact accelerometer which utilizes multiple self-mixing optical interferometers. The device is also a micro-opto-electro-mechanical systems (MOEMS) sensor. The interferometers are used to detect acceleration as well as monitor the wavelength, temperature, and refractive index and perform differential measurements. In addition, photodetectors are employed to monitor the input optical power.

Abstract: A refractive-index measurement system includes a light source, a first beam splitter, a first reflective mirror, a second reflective mirror, a second beam splitter, a container, a first polarizer, and a second polarizer. The first beam splitter splits light emitted from the light source into first and second light beams. The first light beam and the second light beam are reflected by the first reflective mirror and the second reflective mirror, respectively, incident into the second light beam splitter. The container is positioned along an optical pathway of first light beam. The container accommodates a lens and is filled with a medium having a refractive index substantially the same as a theoretical refractive index of the lens. The first polarizer is positioned along the optical pathway of the first light beam. The second polarizer is positioned along an optical pathway of the second light beam.

Abstract: An imaging, differential optical sectioning interference microscopy (DOSIM) system and method for measuring refractive indices and thicknesses of transparent thin-films. The refractive index and thickness are calculated from two interferometric images of the sample transparent thin-film having a vertical offset that falls within the linear region of an axial response curve of optically sectioning microscopy. Here, the images are formed by a microscope objective in the normal direction, i.e., in the direction perpendicular to the latitudinal surface of the thin-film. As a result, the lateral resolution of the transparent thin-film is estimated based on the Rayleigh criterion, 0.61?/NA.

Abstract: The present invention relates to systems and methods for quantitative three-dimensional mapping of refractive index in living or non-living cells, tissues, or organisms using a phase-shifting laser interferometric microscope with variable illumination angle. A preferred embodiment provides tomographic imaging of cells and multicellular organisms, and time-dependent changes in cell structure and the quantitative characterization of specimen-induced aberrations in high-resolution microscopy with multiple applications in tissue light scattering.

Abstract: A method of operating a wavefront interferometry system that generates an array of interference signals that contains information about relative wavefronts of measurement and reference beams, the method involving: from the array of interference signals, computing a first array of phase measurements for a first time and a second array of phase measurements for a second time; computing a difference of the first and second arrays of phase measurements to determine an array of rates of phase changes; and from the array of rates of phase changes, computing an array of atmospheric turbulence effect values which is a measure of atmospheric turbulence effects in the wavefront interferometry system.

Abstract: A interferometer-based fouling detection system and method are described. The system may include a fiber optic cable, a light source in communication with the fiber optic cable, at least one photo detector in communication with the fiber optic cable, and at least one interferometric spectrometer. The fiber optic cable may include a long period grating and a fiber Bragg grating or it may include a facet edge. The system may instead include a fiber optic cable, a light source in communication with the fiber optic cable, at least one photo detector in communication with the fiber optic cable, a fiber coupler, a reference probe including a mirror, a sample probe, and an interferometer.

Abstract: Methods and compositions are provided for detecting biomolecular interactions. The use of labels is not required and the methods can be performed in a high-throughput manner. The invention also provides optical devices useful as narrow band filters.

Abstract: Methods for measuring a property of a sample material present at an interface of an emerging medium in a spectroscopic device include a sensor (10) featuring at least one dielectric member (14) disposed upon a entrant medium (12), with the dielectric member being of an optical thickness selected to produce an observable interference effect for an incident angle of light below the critical angle of total internal reflection at the interface with the dielectric member (14). The dielectric member (14) of the sensor device (10) may be modified and functionalized for binding of a sample analyte by disposing a sensing surface area (38, 40, 42) upon it. Moreover, an metal layer (18) may be added to an entrant medium (20) to produce a sensor (16) that generates observable optical phenomena both above (resonance) and below (interference) a given critical angle.

Abstract: The aim of the invention is to determine the refractive index and/or compensation of the influence of the refractive index during interferometric length measurement with the aid of an interferometer (13, 13?) impinged upon by at least two measuring beams (v2, v3) having at least defined frequencies with an approximately harmonic ratio. Interferometric phases are evaluated for the at least two measuring beams (v2, v3) at the outlet of said interferometer. The interferometric phases corresponding to the harmonic ratio of the frequencies of the measuring beams (v2, v3) are multiplicated and at least one phase difference of the thus formed phase value is examined.

Abstract: A fluid analysis element includes: a semi transmissive/semi reflective first reflector; a transmissive apertured member, having a plurality of apertures, with diameters sufficiently smaller than the wavelength of measuring light, formed therein for holding a fluid sample; and a second reflector, which is fully reflective or semi transmissive/semi reflective. The first reflector, the transmissive apertured member, and the second reflector are provided in this order from the side of the element into which the measuring light enters. Emitted light is emitted from the first reflector or the second reflector. The element displays absorption properties that absorb light of specific wavelengths according to the mean complex refractive indices of the first and second reflectors, and the mean complex refractive index and the thickness of the transmissive apertured member.

Abstract: The present invention relates to a method for assessing the purity of vegetable oils by means of THz time-domain spectroscopy, comprising the steps of: measuring the THz time-domain spectra of standard vegetable oils to establish a spectral database; measuring the THz time-domain spectrum of vegetable oil to be detected; analyzing the purity of the detected vegetable oil based on the pre-built database. The present invention also relates to an apparatus for assessing purity of vegetable oil by means of THz time-domain spectroscopy, comprising: spectrum measuring device for measuring time-domain waveforms of THz pulses before and after transmitting the vegetable oil held in a container by transmission approach, or directly measuring time-domain waveforms of THz pulses before and after reflecting from the vegetable oil by reflection approach; and data processing device for extracting physical parameters of the vegetable oil in THz region according to the time-domain waveforms.

Abstract: An image processing apparatus is disclosed which can produce refractive index distribution data with high accuracy without limiting directions in which transmitted wavefronts are measured. The image processing apparatus has a simulating section which simulates a transmitted wavefront in each of the directions to produce a second transmitted wavefront image based on first refractive index distribution data, a comparing section which produces first information indicating the result of comparison between the second transmitted wavefront image and the first transmitted wavefront image, and a changing section which changes the first refractive index distribution data based on the first information to produce second refractive index distribution data.

Abstract: The present invention provides methods for generating interferometric information. Interferometric information from refractively scanned interferometers can contain errors due to wavelength-dependent refractive indices. The wavelength-dependent refractive indices of elements of the interferometer can produce errors when the OPD at a reference wavelength is different than the OPD at a sample wavelength. The invention can provide correction of interferometric information using relationships between the OPD at the wavelengths of interest, which correction can also be dependent on physical relationships among elements of the interferometer.

Abstract: A photonic crystal (PC) based structure is proposed for sensing exceptionally small refractive index changes of a medium. In a typical photonic crystal, the location of the band edges and the defect modes if present are very sensitive to the dielectric contrast of the structure. Hence, a propagating electromagnetic wave at a particular frequency gains significant phase shift due to the index changes and when this phase shift is measured interferometrically, it could be possible to infer the refractive index changes as small as 10?11 per lattice distance. Furthermore any other effect that changes the band edge positions (dispersion diagram) of the photonics crystal structure such as binding an analyte to surface of photonic crystal structure will cause detectable phase change in the output wave which will indicate the amount of the analyte. This method can be used to sense biological, biochemical, chemical and refractive index sensing of gases and liquids.

Abstract: Provided are target detection substrate for target detecting apparatuses capable of detecting various targets such as pathogens, biological substances and toxic substances without using a costly measuring apparatus; which can detect these targets with a low measurement error, high efficiency, simplicity, speed and sensitivity; and which can make a quantitative detection thereof. The target detection substrate includes at least a target interaction part which can interact with a target on an optical interference substrate, which optical interference substrate includes a substrate and a different refractive index film having a different refractive index from that of the substrate disposed on the substrate, and interferes irradiated light to radiate it as interference light where the total number of peak tops and peak bottoms in a graph of transmittance against wavelength of the interference light is from 1 to 20 in an arbitrary wavelength range of 100 nm.

Abstract: Device and method for measuring complex reflectance using a light source for generating a light beam with known polarization state, a lens for focusing the beam onto a sample surface such that various rays within the focused beam create a spread of angles of incidence ?, a waveplate for retarding one polarization state of the beam, a polarizer for generating interference between beam polarization states, and a detector with a two dimensional array of detector elements for generating intensity signals in response to the beam, wherein each detector element corresponds to a unique angle of incidence ? and azimuthal angle ? of the reflected beam. A processor calculates magnitude and phase values for the reflected beam by using the intensity signals corresponding to at least one incident angle ? and a plurality of azimuthal angles ? within the at least one incident angle ? sufficient to enable a meaningful Fourier analysis thereof.

Abstract: In general, in one aspect, the invention features a method that includes directing a first measurement beam along a first path contacting a measurement object to determine a first interferometric phase related to a position of a measurement object, directing a second measurement beam along a second path contacting the measurement object to determine an second interferometric phase related to the position of the measurement object, and determining a contribution to the first interferometric phase due to perturbations in refractivity along the first path based on the second interferometric phase.

Abstract: A noninvasive testing system using a method of testing a device under test by providing a beam of light from a light source having a first wavelength, and in a first beam instance imposing the beam of light on a test device when the test device has a first state of refractive indexes, and in a second beam instance imposing the beam of light on the test device when the test device has a second state of refractive indexes, in both instances the beam of light being imposed on the test device over a spatial region within the test device substantially greater than the first wavelength. Data resulting from the interference of the first beam instance and the second beam instance within the device under test is obtained representative of the voltages within the region. The first state of refractive indexes is at a first voltage potential, and the second state of refractive indexes is at a second voltage potential different from the first voltage potential.