Abstract: The invention provides a Stokes parameter measurement device and Stokes parameter measurement method that enable high-precision measurement. The Stokes parameter measurement device comprises a polarization splitting device which comprises an optical element formed of a birefringent crystal material and which, by means of the optical element, splits signal light to be measured into a plurality of polarized light beams and adjusts the polarization state of one or more among the plurality of polarized light beams, and a light-receiving portion for performing photoelectric conversion of an optical component of the signal light split by and emitted from the polarization splitting device.

Abstract: A treatment pattern (such as a focused spot, an image, or an interferogram) projected on a treatment target may lose precision if the treatment beam must pass through a birefringent layer before reaching the target. In the general case, the birefringent layer splits the treatment beam into ordinary and extraordinary components, which propagate in different directions and form two patterns, displaced from each other, at the target layer. The degree of birefringence and the orientation of the optic axis, which influence the amount of displacement, often vary between workpieces or between loci on the same workpiece. This invention measures the orientation of the optic axis and uses the data to adjust the treatment beam incidence direction, the treatment beam polarization, or both to superpose the ordinary and extraordinary components into a single treatment pattern at the target, preventing the birefringent layer from causing the pattern to be blurred or doubled.

Abstract: An optical filter assembly having selectable bandwidth is presented. The optical filter assembly includes a first optical filter, a first optical retarder with optical retardance R1, a second optical retarder with optical retardance R2, a polarization switch positioned between the first and second retarders which causes their retardances to substantially add in a first switch setting and to substantially subtract in a second switch setting, and an exit polarizer. A multispectral imaging system using tunable optical filters having selectable bandwidth is presented. A method of filtering light is also presented. The method includes providing a first optical filter, providing a dynamic bandwidth stage including a polarization switch, selecting a first setting of the polarization switch, and producing a first filter action for light passing through the first filter and the dynamic bandwidth stage.

Abstract: An influence on a sensor output is suppressed to a minimum degree even in the case when there is a ripple in a light source, thereby improving the measurement accuracy. In an intensity modulation type optical sensor, light from a light source 1 is guided to a sensor head 6, the intensity of the light is modulated on the basis of an alternating current (AC) measured object (for example, a current i) changing with time, the modulated light is received in a light receiving element 81 and converted into an electrical signal, and a normalized received signal Xs indicating a degree of modulation is acquired from a ratio of an AC component As and a DC component Ds of the electrical signal to thereby acquiring a value of the AC measured object.

Abstract: Methods and apparatus to perform wavefront analysis, including phase and amplitude information, and 3D measurements in optical systems, and in particular those based on analyzing the output of an intermediate plane, such as an image plane, of an optical system. Measurement of surface topography in the presence of thin film coatings, or of the individual layers of a multilayered structure is described. Multi-wavelength analysis in combination with phase and amplitude mapping is utilized. Methods of improving phase and surface topography measurements by wavefront propagation and refocusing, using virtual wavefront propagation based on solutions of Maxwell's equations are described. Reduction of coherence noise in optical imaging systems is achieved by such phase manipulation methods, or by methods utilizing a combination of wideband and coherent sources.

Abstract: A system for measuring linear or circular diattenuation in an optical element includes a sample rotation stage for securing an optical element sample; a light source module for generating a source light beam and a detector module. The light source module and detector module are arranged with the sample rotation stage between them, thereby permitting the source light beam to propagate through a sample that may be secured in the sample stage and to the detector module. Linear motion control of the light source module and the detector module, as well as tilt control of the light source module, the sample rotation stage and the detector module is provided, thereby to facilitate detection, by the detector module of the modulated light intensity information corresponding to a diattenuation characteristic of the optical sample secured in the sample stage.

Abstract: Disclosed is a system for aligning a 3D image display device. The system for aligning the 3D image display device comprises: a display panel showing a left eye image and a right eye image, and having a display panel align mark at a circumference of the display panel; a plurality of 3D filter including a transparent substrate, and a retarder converting a left eye image into a first polarized light and a right eye image into a second polarized light on the transparent substrate; a plurality of 3D filter align mark having a retarder pattern formed at a circumference of the 3D filter on the transparent substrate of the 3D filter, and a reflection plate formed on the retarder pattern; and a vision system taking pictures of the display panel align marks and the 3D filter align marks.

Abstract: A crystal optical material is illuminated at a wavelength of light that does not ionize the crystal optical material. Birefringence is measured between a plurality of voxels within the crystal optical material having spatial dimensions small enough to distinguish optical propagations of the light encountering boundary regions between subgrains of the crystal mosaic from optical propagations of the light through the subgrains themselves. The measured birefringence is evaluated for quantifying a characteristic of the crystal matrix. Metrics describing the crystal matrix are associated with performance of the crystal optical material.

Abstract: A method of controlling a light beam in an optical system includes a light source that directs a collimated light beam along a path, through a sample, and toward the active area of a stationary detector. The method includes the step selectively moving a lens into the path of the light beam for spreading the beam in instances where the path of the beam is altered by the sample between the source and the stationary detector The detector, therefore, is held stationary. Adjustment means are provided for increasing the intensity characteristic of the light that reaches the detector to account for a decrease in intensity that occurs when the lens is in the path of the light beam to spread the beam.

Abstract: The invention provides a Stokes parameter measurement device and Stokes parameter measurement method that enable high-precision measurement. The Stokes parameter measurement device comprises a polarization splitting device which comprises an optical element formed of a birefringent crystal material and which, by means of the optical element, splits signal light to be measured into a plurality of polarized light beams and adjusts the polarization state of one or more among the plurality of polarized light beams, and a light-receiving portion for performing photoelectric conversion of an optical component of the signal light split by and emitted from the polarization splitting device.

Abstract: A method, apparatus, and computer program product for identifying features in a sample by analyzing Mueller matrices to calculate an average degree of polarization, a weighted average degree of polarization, a degree of polarization map, a degree of polarization surface. Also, a method, apparatus, and computer program product for identifying features in a sample by analyzing Mueller matrices to calculate depolarization relative to a retardance axis and/or a diattentuation axis, and to calculate a ratio of diattenuation to polarizance or ratios of row and column magnitudes. Also, a method for retinal polarimetry, including a non-depolarizing light tube configured for insertion into the eye.

Abstract: The present invention provides systems and methods for data acquisition and image analysis that utilize twisted nematic liquid crystals (“TNLCs”) to create maps of bio/chemical functionality patterned on surfaces. The method involves the acquisition of a series of images of TNLC film that contacts the analytic surface followed by analysis of the series of images to yield maps of twist angle of the liquid crystal across the surface. This analysis technique effectively condenses a large data set (stack of images) into a compact form (map of twist angle), revealing features on the surface that were not apparent in the individual images comprising the original stack.

Abstract: A method of evaluating a color filter including a substrate, and at least three color pixels disposed thereon, the method includes determining an oblique visibility of a liquid crystal display device equipped with the color filter on the basis of value ?1 obtained from the equation (1): ?1=?ab?(?)·T(?)d???(1) wherein “a” and “b” are values respectively representing a wavelength range of a continuous wavelength light and satisfying conditions of 380?a, b?780 and a<b; ?(?) represents an optical retardation obtained by irradiating each of color pixels with a continuous wavelength light containing light components with wavelength ? falling within a range of 380 nm to 780 nm at an incident angle, and subjecting the transmitted light to measurement using a spectroscopic ellipsometer, and T(?) represents a spectral transmittance of the color pixels measured at the wavelength ? falling within a range of 380 nm-780 nm.

Abstract: The optical axis orientation measuring device according to the present invention is a reflective optical axis orientation measuring device for a spherical member made from a single crystal of an optically uniaxial crystal having birefringence, comprising: illuminating means for illuminating the spherical member through a polarizer; and isogyre observing means for observing the isogyre that is structured by the light that is reflected from the bottom surface of the spherical member and emitted from the spherical member through an analyzer that has a cross-nicol relationship with the polarizer.

Abstract: To provide a method for detecting the equatorial plane, capable of detecting directly an equatorial plane that has the optical axis as the axis thereof, in a spherical optically uniaxial crystal. The method for detecting the equatorial plane as set forth in a first form of the present invention is a method for detecting an equatorial plane of a spherical member made from a single crystal of an optically uniaxial crystal having birefringence, comprising: a step for causing light to be incident on the spherical member through a polarizer; and a step for observing the isogyre that is structured by the light that is emitted from the spherical member through an analyzer that has a cross-nicol relationship with the polarizer; wherein the isogyre is an isogyre that is observed when the oscillating direction of the polarizer or the analyzer is near to parallel with the optical axis of the spherical member.

Abstract: Apparatus, systems and techniques for measuring optical spectral property such as the frequency and the optical spectrum of light based on polarization analysis.

Abstract: Optical devices based on internal conical refraction for developing new set-ups, methods and applications based on the specific properties of internal conical diffraction. The devices include several set-ups, methods and applications consisting of biaxial crystal(s)—one or more polarization elements and optical elements. The biaxial crystal is an optical crystal which may belong to the trigonal, orthorhombic or trigonal crystal classes.

Abstract: A method and apparatus for accurately retrieving the position of an optical feature. The method uses the optical properties of biaxial crystals to conically refract the optical feature and transform the image of the optical feature to a circular ring structure. The position of the optical feature is then calculated by locating a center point associated with the circular ring structure.

Abstract: A receiver including an analyzer and a detector coupled to the output of the analyzer. The analyzer selects a polarized component of a return beam for input to the detector. The analyzer may be linear, circular or elliptical. Coupled with a laser adapted to output a polarized beam, the receiver provides an active optical target detector. An arrangement may be included for compensating for rotation and ellipticity in the returned beam. In one embodiment, the arrangement for compensating for rotation of the orientation of linear polarization in the returned beam includes a Faraday rotator positioned between the transmitter and the analyzer. An arrangement is disclosed for varying the rotation in the returned beam using a Faraday rotator until a maximum transmittance is achieved. In an alternative embodiment, the arrangement for compensating for ellipticity in the returned beam includes an electro-optical modulator positioned between the transmitter and the analyzer.

Abstract: An apparatus, for measuring an electric field while minimally perturbing the electric field being measured, includes an analyzing stage and a sensor head. The sensor head is optically coupled to the analyzing stage by a laser probe beam transmitted from the analyzing stage. The sensor head includes an electro optic crystal disposed between two gradient index lenses, where the first gradient index lens emits a laser beam transmitted from the analyzing stage to the sensor head, where the electric field is applied and where, the electro optic crystal transforms the laser beam probe into a phase modulated laser beam. The second gradient index lens transmits the phase modulated laser beam back to the analyzing stage, where polarization optics and a photodetector convert the phase modulated laser beam into an electrical signal representing field strength and phase of the electric field.

Abstract: A polarization duobinary optical transmitter is disclosed. The transmitter includes a precoder for coding an electric signal and a light source for generating continuous light. The transmitter also includes a chirped-free modulator for generating an NRZ signal including first and second polarization light beams orthogonal to each other by modulating the light with the electric signal and a band-pass filter for limiting neighbor frequency bands between the first and second polarization light beams.

Abstract: Embodiments of the invention include a SCOL targeting groups configured to increase target to target separation and thereby increase target utility to simultaneous exposures to multiple illumination dots and associated inspection methodologies. The embodiments of the invention further relate to apparatus for projection simultaneous illumination dots onto different targets of the same targeting group on a wafer to conduct multiple simultaneous target inspections. Embodiments of the invention further relate to methods used to inspect SCOL targets using simultaneous illumination dots directed onto different targets of the same targeting group to conduct multiple simultaneous target inspections.

Abstract: A sensor for measuring in a borehole at least one of orientation, acceleration and pressure, the sensor including: a light source; a birefringent material receiving light from the source; and a photodetector for measuring light transmitted through the birefringent material to measure the at least one of orientation, acceleration and pressure.

Abstract: A variety of toy polariscopes are simpler in design and less costly than precision instruments used in scientific research and stress analysis of materials and structures. The toy polariscopes are designed for a variety of objects that may exhibit photoelastic properties such as glass, plastic, Plexiglas, gel candle material and other gels, and even edible photoelastic objects. They are specially designed for objects of various sizes with a variety of purposes such as objects to enhance learning in a variety of conditions and experiences. Special objects are designed to go with the toy polariscopes such as edible and inedible photoelastic objects, photoelastic candle material, a variety of photoelastic/photoplastic stands capable of a variety of displays in interaction with other designed photoelastic objects capable of a variety of interaction and displays. Other optical phenomena may also be observed.

Abstract: A toy, art object, decoration, ornament, entertainment device, advertising device, paperweight, or other device is made of a soft deformable plastic material in shapes of prisms, lenses, wedges, cubes, pyramids, as well as other forms that display the changing stress patterns formed by deformations of the photoelastic material. Magnets embedded in the material apply forces that create new patterns. Polarizing films within, or covering the clear plastic enhance the viewing effects. External forces, such as manual manipulation, springs, strings, elastic bands, clamps and other devices are used to create interesting optical effects. The viewing effects increase the entertainment and aesthetic value of the devices.

Abstract: An optical detection system for use in flow cytometry or the like, which includes a polarizing beamsplitter 820 such as a Wollaston prism. A light source provides an input light beam to a flow stream, wherein the input light beam has a polarization direction. The particles in the flow stream may produce an output light beam that includes a polarized component and a depolarized component. The polarizing beamsplitter receives the output light beam, and provides a polarized light beam and a depolarized light beam to a pair of detectors. The pair of detectors provide a first output signal that corresponds to the polarized light beam and a second output signal that corresponds to the depolarized light beam. A controller or processor may use the first output signal and the second output signal to help identify/classify particles and/or particle characteristics in the flow stream.

Abstract: An optical signal is compressively sampled. An optical component with a plurality of transmissive elements and a plurality of opaque elements is created. The location of the plurality of transmissive elements and the plurality of opaque elements is determined by a transmission function. A spectrum of the optical signal is dispersed across the optical component. Signals transmitted by the plurality of transmissive elements are detected in a single time step at each sensor of a plurality of sensors dispersed spatially with respect to the optical component. Each sensor of the plurality of sensors produces a measurement resulting in a number of measurements for the single time step. A number of estimated optical signal values is calculated from the number of measurements and the transmission function. The transmission function is selected so that the number of measurements is less than the number of estimated optical signal values.

Abstract: A substantially achromatic multiple element compensator system for use in wide spectral range (for example, 190-1700 nm) rotating compensator spectroscopic ellipsometer and/or polarimeter systems. Multiple total internal reflections enter retardance into an entered beam of electromagnetic radiation, and the elements are oriented to minimize changes in the net retardance vs. the input beam angle resulting from changes in the position and/or rotation of the system of elements.

Abstract: A substantially achromatic multiple element compensator system for use in wide spectral range (for example, 190-1700 nm) rotating compensator spectroscopic ellipsometer and/or polarimeter systems. Multiple total internal reflections enter retardance into an entered beam of electromagnetic radiation, and the elements are oriented to minimize changes in the net retardance vs. the input beam angle resulting from changes in the position and/or rotation of the system of elements.

Abstract: A polarization controller is configured to comprise polarization state monitoring section for monitoring polarization states of input light and output light of a variable polarization light element; and a control section, when the positions on a Poincare sphere expressing each of the polarization states monitored by the polarization state monitoring section are at the positions being symmetric or approximately symmetric for the equator of the Poincare sphere, for rotating the Poincare sphere by ? by using the earth axis of the Poincare sphere as a rotation axis by changing the azimuth of the optical axis of the variable polarization light element, and also for inverting the changing direction of the phase shift amount. By this, arbitrary and endless control of polarization light can be realized by a phase shift amount being less than the wavelength ? of the input light.

Abstract: A device for polarization-specific examination of an optical system having a detector part that has polarization detector means for recording the exit state of polarization of radiation emerging from the optical system. Also, an associated optical imaging system, and a calibration method for the device. The device includes a polarization detector with a polarizing grating structure. Provided as an alternative is a device for snapshot polarimetry having a birefringent element and downstream polarizer element that adequately polarizes nonquasi-parallel radiation. The device may be used for determining the influence on the state of polarization of UV radiation by a microlithographic projection objective.

Abstract: Methods and apparatus for detecting variations in electromagnetic fields, in particular, terahertz (THz) electromagnetic fields, are provided. The methods and apparatus employ polarization detection devices and controllers to maintain or vary the polarization of modulated signals as desired. The methods and apparatus are provided to characterize electromagnetic fields by directing the electromagnetic field and a probe beam upon an electro-crystal and detecting the modulation of the resulting probe beam. Detection of the modulation of the probe beam is practiced by detecting and comparing the polarization components of the modulated probe beam. Aspects of the invention may be used to analyze or detect explosives, explosive related compounds, and pharmaceuticals, among other substances. A compact apparatus, modular optical devices for use with the apparatus, sample holders, and radiation source mounts are also disclosed.

Abstract: An optical signal is copressively sampled using an imaging system. The imaging system is created from a plurality of subimaging systems. Each subimaging system comprises a subaperture and a plurality of sensors. The optical signal is collected at each subaperture of the plurality of subimaging systems at a single time step. The optical signal is transformed into a subimage at each subimaging system of plurality of subimaging systems. The subimage includes at least one measurement from a plurality of sensors of each subimaging systems. An image of the optical signal is calculated from the sampling function and each subimage, spatial location, pixel sampling function, and point spread function of each subimaging system of the plurality of subimaging systems. The sampling function is selected so that the number of measurements from a plurality of subimages is less than a number of estimated optical signal values in the image.

Abstract: An optical measurement apparatus and method a method for performing modulation spectroscopy measurement of a sample comprising: delivering an incident probe beam to a sample at a known spot; modulating reflectance of the probe beam with a pump beam which periodically forms a pump beam spot on the sample coincident with the probe beam spot; and monitoring a reflected probe beam with a detector: wherein the incident probe and pump beams are collinear; and wherein the incident beams are directed to be collinear by reflecting a beam from a facet of an optical waveguide transmitting the other beam.

Abstract: Sensor interrogation systems based on optical phase changes are configured to quantify analytes. Sensor chips and wells can include light scattering regions, light absorbing regions, or tilted regions to reduce or eliminate unwanted portions of an interrogation optical beam. In some examples, a spatial phase modulation is used to compensate static birefringence or to provide a selected sensor bias point. Phase changes can be detected based on state of polarization using interferometry. Optical resonator structures can be used to enhance phase changes to simplify detection of optical phase changes.

Abstract: A small and high-speed polarization analysis device and ellipsometer having no driving section are provided by overlapping one polarizer array rendered by arranging a plurality of polarizer regions of mutually different optical axis directions in the form of stripes and one wavelength plate array rendered by arranging a plurality of wavelength plate regions of fixed retardation and mutually different optical axis directions in the form of stripes so that the respective stripes of the plurality of polarizer regions and of the plurality of wavelength plate regions intersect one another and by disposing a light-receiving element array so that the intensities of light that has passed through the matrix-like intersection parts can be individually measured.

Abstract: The present invention relates to an optical scanning device that comprises a light source to emit a beam of light, and a beam splitter to split that beam into several beamlets, and further a first objective lens to direct said beamlets onto a focal plane wherein each of said beamlets impinges on the focal plane spacially separated from each other, wherein the beam splitter comprises several birefringent elements for splitting said beam, preferably a stack of Wollaston prisms.

Abstract: A method and a device for processing birefringent and/or optically active materials, wherein a light source (3) for polarized light and an analyzer assembly (8) and a light sensor (9) connected therewith are provided, so that between said components a processing of the birefringent and/or optically active material can be performed, so that the length of the pass-through path of the light through the material to be processed is changed, wherein the light is detected and processed simultaneously in a continuous or intermittent manner at the light sensor placed after the analyzer assembly, so that conclusions are derived from the changes of the light properties at the light sensor with respect to the processing state. Also provided is a combination phase plate manufactured accordingly.

Abstract: In an optical inspection tool, an image of an object under inspection, such as a semiconductor wafer, may be obtained using imaging optics defining a focal plane. Light comprising the image can be split into portions that are detected using multiple detectors which each register a portion of the image. The image of the object at the focal plane can be split into two, three, or more parts by polarization-based beam splitters and/or lenses positioned tangent to the focal plane. The splitting apparatus may comprise a pair of arrays of half-cylinder lenses comprising a convex side and a flat side. The arrays can be positioned with the cylinder axes perpendicular to one another and the flat sides facing each other. Thus, the pair of arrays can divide incoming light into a plurality of rectangular portions without introducing non-uniformities which would occur if several spherical lenses are configured for use in a rectangular array.

Abstract: A spectrophotometer, reflectometer, ellipsometer polarimeter or the like system having a detector means for independently intercepting electromagnetic radiation reflected from a sample frontside or backside, and methodology for pursuing less correlated determination of refractive index and thickness values.

Abstract: Provided are methods for determining the birefringence level of optical material such as polymeric film. In one embodiment, the method uses a setup of optical components that has known system reference angle. The sample may be a stretched polymeric film that has a fast axis angle that has a predetermined orientation in the sample. The system is operated to align the direction of the fast axis of the sample with the reference angle of the system and to measure the birefringence level at a location of the sample. As one aspect of the invention, embodiments and methods are described for accurately determining birefringence levels across a very wide range and up to tens of thousands of nanometers.

Abstract: An imaging polarimeter includes a polarization dispersing element, a spatial light modulator, a complementary polarization dispersing element, a polarization analyzer, an electronic detection plane, and a processor. The polarization dispersing element polarimetrically disperses an image of an object. The spatial light modulator spatially modulates the polarimetrically dispersed image. The complementary polarization dispersing element polarimetrically combines the spatially modulated and polarimetrically dispersed image. The polarization analyzer mixes orthogonal input polarizations with the polarization states of the polarimetrically combined spatially modulated image. The electronic detection plane measures the polarimetrically combined spatially modulated image that includes mixed polarization states.

Abstract: A method and apparatus are provided for determining the first and second order polarization mode dispersion (PMD) vectors of an optical device, such as a single mode optical fiber, using only a single input polarization state. This is achieved by passing light beams having a fixed polarization state and frequencies that vary over a range through the optical device that is being tested. The output polarization states of the light beams that have passed through the optical device are measured, and used to form a curve in Stokes space on a Poincare sphere. The shape of this curve is used to approximate the first and second order (and possibly higher order) PMD vectors, using formulas based on differential geometry.

Abstract: A device for measuring polarization mode dispersion (PMD) in a device under test (DUT) includes a polarized light source for launching a test beam through the DUT, and a PMD analyzer, which uses one of a plurality of known techniques, e.g. fixed analyzer-Fourier transform (FA-FT) or interferometric, to calculate the PMD from the DUT. A passive depolarizer, made up of a plurality of birefringent elements is disposed between the light source and the PMD analyzer to generate a plurality of carrier frequencies that correspond to the delays imposed by the birefringent elements. The PMD content of the DUT is present around each of the carriers, and the plurality of PMD measurements can be averaged to obtain a more accurate and repeatable measure of the PMD.

Abstract: To effectively reduce a measurement error in a parameter indicating two-dimensional spatial distribution of a state of polarization generated by variations in retardation of a birefringent prism pair due to a temperature change or other factors, while holding a variety of properties of an imaging polarimetry using the birefringent prism pair. By noting that reference phase functions ?1(x, y) and ?2(x, y) are obtained by solving an equation from each vibration component contained in an intensity distribution I(x, y), the reference phase functions ?1(x, y) and ?2(x, y) are calibrated concurrently with measurement of two-dimensional spatial distribution S0(x, y), S1(x, y), S2(x, y), and S3(x, y) of Stokes parameters.

Abstract: A method and system are presented for use in measuring/inspecting a patterned article. Optical measurements are applied to a measurement site on the article by illuminating the measurement site with a plurality of wavelengths at substantially normal incidence of the illuminating light, detecting light returned from the illuminated site, and generating measured data indicative thereof. The measurements are applied to the measurement site through a polarizer rotatable between its different orientations selected from a number of pre-calibrated orientations.

Abstract: A process monitoring system has a process chamber configured to hold an object to be processed, an illumination source configured to emit a light to the object, a polarizer configured to polarize the light, a monitor window having a birefringent material and provided on the process chamber to propagate the light, direction adjusting equipment configured to adjust a relationship between a polarization plane of the light and a direction of an optic axis of the monitor window, and a monitoring information processor configured to detect the light reflected from the object.

Abstract: An ellipsometer includes an optical component and a detector. The optical component has two birefringent parts in optical communication via a border surface. Light incident on the border surface is split into two reflected and two transmitted components. The detector is configured to measure a property of at least three out of the four components. Based on the measured properties, a state of polarization of the incident light may be determined.

Abstract: The disclosure is directed to precise measurement of out-of-plane birefringence properties of samples of transparent optical material. Two angled-apart light beams are passed through a selected location of a sample optical element. One of the beams is incident to the sample surface. The characteristics of the beams are detected after passing through the sample, and the information detected is processed to determine the out-of-plane birefringence.

Abstract: A method for determining the optical retardation and birefringence values of an anisotropic material utilizing a Fourier transform near infrared spectrophotometer operated in at least a portion of the range of wavenumbers between about 4,000 to about 10,000 cm?1.