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.

Abstract: A polarization stabilizing device and method based on controlling the phase retardation of a pair of variable phase retarders with a controller such that the first of the variable retarders has its phase retardation switched between first and second values whenever the phase retardation of the second of the variable retarders reaches an upper or a lower limit. The upper and lower limits of the second retarder and the first and second values of the first retarder are chosen so that discontinuities in the power of the output optical signal are avoided when the first variable retarder is switched, thereby providing endless polarization stabilization using phase retarders that themselves have only limited retardation ranges.

Abstract: An optical signal emitted from a semiconductor laser is converged by a lens and then received by a single uniaxial birefringent crystal having a C axis that is inclined at an angle other than 90 degrees against a laser optical axis to output an optical signal having a polarized wave component of constant intensity corresponding to the wavelength of the optical signal regardless of temperature changes. The optical signal has an ordinary ray vibrating in a direction perpendicular to a plane including both the C axis and the laser optical axis, and an extraordinary ray vibrating in a direction perpendicular to both the ordinary ray and the laser optical axis. A first main photo detector detects the intensity of a p-polarized component of the optical signal that has passed through a polarizer and a second photo detector directly receives the optical signal converged by the lens.

Abstract: Systems and methods for producing circular extinction (CE) contrast images of anisotropic samples. Microscope systems for determining circular extinction (CE), the differential transmission of left and right circularly polarized light resulting from circular dichroism (CD) of an anisotropic sample, include mechanically driven optical components and an image detector such as a monochromatic CCD camera to detect light intensities. In one aspect, optical components include a tunable filter, a rotatable linear polarizer and a variable retarder. The tunable filter is adjustable to provide light at a specific desired wavelength. The linear polarizer is adjustable to provide linearly polarized light with a specific wave vector, and the variable retarder is adjustable to produce near perfect circular polarized light at every selected wavelength.

Abstract: A scanning laser polarimetry (SLP) system that measures retinal nerve fiber layer (RNFL) retardance in a single scan image with improved sensitivity. An external bias retarder in combination with the anterior segment retardance forms a nonzero joint retardance adapted to enhance the signal-to-noise ratio (SNR) of the SLP system. With such a simple bias retarder, the effects of anterior segment retardance (?C, ?C) may be removed from a single polarimetric image of the retina without a direct cancellation by a variable corneal compensator (VCC) by the method of this invention. Using a single polarimetric image is particularly advantageous for simplicity and accurate corneal compensation. The simple bias retarder may be embodied as a VCC or any useful external retarder, for example.

Abstract: Improved methodology for monitoring deposition or removal of material to or from a process and/or wittness substrate which demonstrates a negative e1 at some wavelength. The method involves detection of changes in P-polarized electromagnetism ellipsometric DELTA at SPR Resonance Angle-of-Incidence (AOI) to monitor deposition of and/or removal of minute amounts of materials onto, or from, said process and/or witness substrate. The methodology can optionally monitor ellipsometric PSI, and involves simultaneously or sequentially applying non-P-polarized electromagnetism at the same angle of incidence, or electromagnetic radiation of any polarization at a different angle-of-incidence and wavelength to the process or wittness substrate and application of conventional ellipsometric analysis.

Abstract: A transmission mask or cooled aperture is used in spectroscopy to compressively sample an optical signal. The locations of transmissive and opaque elements of the mask are determined by a transmission function. The optical signal transmitted by the mask is detected at each sensor of a plurality of sensors dispersed spatially with respect to the mask. A number of estimated optical signal values is calculated from sensor measurements and the transmission function. The optical signal is compressed by selecting the transmission function so that the number of measurements is less than the number of estimated optical signal values. A reconstructed optical signal is further calculated using signal inference. An imaging system created from plurality of encoded subimaging systems compressively samples an optical signal.

Abstract: Systems and methods for measuring stress in a specimen are provided. One system includes an optical subsystem configured to measure stress-induced birefringence in patterned structures formed on the specimen. In some embodiments, the optical subsystem may be configured as a spectroscopic ellipsometer, a multi-angle laser ellipsometer, a polarimeter, a polarized reflectometer, or some combination thereof. The system also includes a processor coupled to the optical subsystem. The processor is configured to determine stress in a material of the patterned structures using the stress-induced birefringence measurements. One method includes measuring stress-induced birefringence in patterned structures formed on the specimen using an optical technique. The method also includes determining stress in a material of the patterned structures using the stress-induced birefringence measurements.

Abstract: A system for implementing Berek-type variable retarder plate tipping capability in two orthogonal directions via tipping about a single axis, in combination with a means for rotating the orientation of the axis, having application in ellipsometer and polarimeter and the like systems.

Abstract: A polarization modulation photoreflectance technique has been developed for optical characterization of semiconductor electronic interfaces. By using a laser source in conjunction with polarization state modulation, a polarization modulation spectroscopy technique may be used to characterize the optical response of semiconductor materials and structures. Disclosed methods and instruments are suitable for characterization of optical signatures of electronic interfaces, including characterization of electric fields at semiconductor interfaces.

Abstract: Systems and methods of measuring birefringence or retardation are provided. For some embodiments, a system is provided, which comprises a polarizer, an analyzer, a first waveplate, and a second waveplate. The system is configured to obtain light intensity measurements by recursively rotating the second waveplate. The obtained light intensity measurements are retrieved, and a light transmission intensity curve is determined from the light intensity measurements.

Abstract: A polarization split device that includes an optically isotropic substrate, an optically anisotropic film, and a diffraction grating. The optically anisotropic film is formed on the optically isotropic substrate. The diffraction grating includes first and second cyclically structural portions. The first cyclically structural portion is formed on a front surface of the optically anisotropic film such that a depression in a rectangular shape is cyclically arranged with a predetermined pitch. The second cyclically structural portion includes an optically transparent material having a refractive index approximately equivalent to a refractive index of the optically anisotropic film and is configured to cover the first cyclically structural portion. Diffraction light having a diffraction angle greater than a predetermined angle among diffraction light diffracted by the diffraction grating is inhibited from being discharged outside.

Abstract: A variable polarization independent optical power splitter is disclosed. An input light beam “A” is split into two output light beams “M” and “N” where the optical power ratio of the two output light beams “M” and “N” is adjusted to a desired ratio by controlling a variable polarization rotator, e.g. a liquid crystal unit. The polarization components “P” and “S” of the input light beam “A” are separated in a first polarization separator, then processed through the variable polarization rotator, and a second polarization separator. The polarization independence of the power split is thus achieved through the stratagem of processing the “P” and “S” polarized components of the input light beam “A” separately, resulting in four light beams “H”, “I”, “L” and “K”, which are appropriately combined in the polarization combiner to yield the output light beams “M” and “N” having the desired optical power ratio “R”.

Abstract: Multilayer optical films are comprised of materials with glass transition temperatures below room temperature (<30° C.). The high refractive index polymers are unique in that they exhibit mechanical properties similar to other low Tg semi-crystalline polymers, yet have significant birefringence (>0.05) when strain induced oriented. Novel combinations of comonomers for thermoplastics control the rate of crystallinity for improved processability and flexibility, giving the films crease and crumple recovery advantages.

Abstract: A method and apparatus for measuring birefringent particles is provided comprising a source lamp, a grating, a first polarizer having a first transmission axis, a sample cell and a second polarizer having a second polarization axis. The second polarizer has a second polarization axis that is set to be perpendicular to the first polarization axis, and thereby blocks linearly polarized light with the orientation of the beam of light passing through the first polarizer. The beam of light passing through the second polarizer is measured using a detector.

Abstract: A method for tracking change in Temperature of Uniaxial or Biaxial Anisotropic Samples utilizing polarized electromagnetic radiation.

Abstract: Purging of a light beam path in an effective manner that minimizes the affect of the purging requirement on system throughput. In one embodiment, the invention is incorporated into a birefringence measurement system that has several components for directing light through a sample optical element and thereafter detecting and analyzing the light. The segment of the beam path through the sample is isolated to reduce the volume that requires continual purging.

Abstract: A method and apparatus for sensing temperature using optical fiber is provided. In one embodiment, a method for sensing temperature using optical fiber includes launching a polarized optical signal having sufficient intensity to produce Brillouin scattering of the signal into a polarization maintaining optical fiber, receiving a first signal reflected from the launched signal, receiving a second signal reflected from the launched signal; and resolving a metric indicative of temperature from the first and second received signals. The method is particularly useful for sensing temperature in hazardous locations such as down hole gas and oil field applications or other applications where minimization of strain effects to signal transmission is desired.

Abstract: The disclosure is directed to systems and methods for precisely measuring birefringence properties of large-format samples of optical elements. A gantry-like configuration is employed for precise movement of birefringence measurement system components relative to the sample. There is also provided an effective large-format sample holder that adequately supports the sample to prevent induced birefringence therein while still presenting a large area of the sample to the unhindered passage of light.

Abstract: Provided are systems and methods for precisely measuring birefringence properties of optical elements, especially those elements that are used in deep ultraviolet (DUV) wavelengths. The system includes two photoelastic modulators (PEM) (126, 128) located on opposite sides of the sample (136). Each PEM is operable for modulating the polarity of a light beam that passes though the sample. The system also includes a polarizer (124) associated with one PEM, an analyzer (130) associated with the other PEM, and a detector (132) for measuring the intensity of the light after it passes through the PEMs, polarizer, and analyzer. Described are techniques for determining birefringence properties across a wide range. For example, a dual-wavelength source light embodiment is provided for measuring relatively high levels of birefringence.

Abstract: An anticounterfeiting device comprising a surface relief structure having both diffractive and polarizing properties. Polarization of reflected light is controlled by the orientation and composition of a fine grating structure whose shortest period is substantially smaller than the wavelength of visible light; and diffraction is controlled by a longer period component of the grating structure having a second orientation. Presence and arrangement of the polarizing properties of the device are detected by illuminating the device with polarized light and viewing the reflected light, or by illuminating the device with unpolarized light and viewing reflected light through a polarizer. Because such a device is difficult to copy or reverse engineer precisely, the authenticity of the device can be judged by the presence and arrangement of the polarization properties and the diffraction properties in the device.

Abstract: Timing alignment between a pulse carver (i.e., intensity modulator) and a phase modulator, e.g., in a return-to-zero (RZ) differential phase-shift keying (DPSK) optical transmitter, is monitored by filtering a signal from the transmitter and measuring the power of the filtered signal. In certain embodiments, the filter has a birefringent device (such as a polarization-maintaining fiber) and a polarizer. The polarizer may be a rotating polarizer with a rotating quarter-wave plate in front of it. In other embodiments, the filter is a periodic filter such as a Mach-Zehnder interferometer or an etalon filter. Regardless, the measured power may be used to generate control signals used to variably delay the signals that drive the phase modulator and/or the pulse carver to compensate for detected misalignment. The measured power may also be used to monitor the bit-error-rate degradation caused by timing misalignment between the pulse carver and the phase modulator.

Abstract: A birefringence measurement apparatus includes a measurement part for measuring a birefringence azimuth and a birefringence amount of an object to first and second light having different wavelengths from each other, and a determination part for calculating at least one of a birefringence azimuth and a birefringence amount to third light different in wavelength from the first and second light based on the birefringence azimuth and birefringence amount of the object to the first and second light.

Abstract: A system and method are described herein for determining the quality of an optical material by measuring and analyzing birefringence (e.g., stress-induced birefringence, inherent birefringence) in the optical material (e.g., glass sheet). The method is a scanning technique in which a birefringence sensor is set to a first optical state and then moved in a direction at a constant velocity over a glass sheet while first power transmission measurements are made at a high data rate. At the end of this move, the birefringence sensor is set to a second optical state and then moved at the same velocity back over the glass sheet, while second power transmission measurements are made. This procedure is repeated the same number of times as there are optical states in the birefringence sensor. A computer then calculates birefringence values using profiles of the power transmission measurements so as to determine the quality of the glass sheet.

Abstract: Highly accurate calibration of a polarimeter of the type having at least four detectors involves using four known states of polarisation of an input light signal (calibration polarisations) and at least one further state of polarisation. All input states of polarisation to the polarimeter have unity normalised power of the light signal and unity degree of polarisation. A Stokes matrix for the four calibration polarisations is generated with at least one variable correction parameter, and a correction matrix is determined from the Stokes matrix and a corresponding detector current matrix measured by the polarimeter. An optimisation criterion that is a function of the degrees of polarisation for the states of polarisation as measured by the polarimeter is generated. The correction parameter is varied iteratively to minimise the optimisation criterion so that the polarimeter is calibrated to produce unity power and degree of polarisation for any input state of polarisation.

Abstract: A method and apparatus for sensing temperature using optical fiber is provided. In one embodiment, a method for sensing temperature using optical fiber includes launching a polarized optical signal having sufficient intensity to produce Brillouin scattering of the signal into a polarization maintaining optical fiber, receiving a first signal reflected from the launched signal, receiving a second signal reflected from the launched signal; and resolving a metric indicative of temperature from the first and second received signals. The method is particularly useful for sensing temperature in hazardous locations such as down hole gas and oil field applications or other applications where minimization of strain effects to signal transmission is desired.

Abstract: A method and in-situ sample current amplification system for carrying out failure analysis of integrated circuit semiconductor device conductive portions. The method includes providing an integrated circuit (IC) semiconductor device; providing a pre-amplifier board (PAB) comprising current signal amplification electronics; mounting the IC semiconductor device in electrical communication with the PAB; mounting the PAB comprising the IC semiconductor device in a scanning electron microscope (SEM) for probing the IC semiconductor device with a primary electron beam; exposing at least a portion of the IC semiconductor device to the primary electron beam to induce a current signal within the conductive portions; amplifying the current signal; and, outputting the amplified current signal to an image display system to produce an image representative of an electrical resistance of the conductive portions.

Abstract: Faraday rotators each have a Faraday element which rotates light and a magnetic field generator for applying a magnetic field to the Faraday element. A wavelength plate is disposed between the Faraday rotators and it retards the light. A polarizer transmits, of the light, light having a predetermined plane of polarization which has been rotated by the Faraday rotators and retarded by the wavelength plate. An optical receiver receives the light transmitted by the polarizer and outputs a light receiving signal which corresponds to the amount of light received. A signal generator outputs a control signal for polarizing the light to be measured into at least four polarization states to the magnetic field generator. A signal processor determines Stokes parameters which indicate the polarization state of the light to be measured based on the four polarization states, and the light receiving signal corresponding to each of the four polarization states.

Abstract: A diagnostic system (24) for a PEM (20) provides optically determined information about the retardance characteristics induced by the PEM (20). The diagnostic system (24) is integrated with the PEM (20) so that the PEM (20) performance may be diagnosed or monitored during operation of the PEM (20). Specifically, the diagnostic system (24) is used alongside an optical setup (22) that employs a primary light beam (28) for conventional purposes such as polarimetry, optical metrology, etc. The diagnostic system (24) includes its own diagnostic light source (50) that is directed through the optical element (32) of the PEM (20) at a location remote from the primary aperture (38) of the PEM (20). Thus, the diagnostic system (24) and the primary PEM (20) operation can be undertaken simultaneously, with one not interfering with the other. The output of the diagnostic system reflects the actual retardance characteristic provided by the PEM (20) and can be used as feedback to adjust the PEM control as needed.

Abstract: A particle sizing method and apparatus of the PIDS type uses randomly polarized radiation to irradiate a particle sample. Portions of the resulting side scattering pattern are decomposed to simultaneously produce, for each decomposed portion, first and second linearly polarized beams of radiation in which the respective planes of polarization of the two beams are mutually perpendicular. Each of the polarized beams is focused onto a photodetector, and the respective photodetector outputs are differentiated to provide PIDS signals that are useful in calculating a particle size distribution for the sample.

Abstract: An apparatus and a method of determination of at least one optical parameter of an optical signal includes providing a beam of the optical signal having a diameter, manipulating the beam, the manipulation having polarization properties, the properties being dependent of the position in the beam laterally with respect to a direction of propagation of the beam during manipulation, detecting in intensities at least three parts of the beam in their dependence of the position in the beam laterally with respect to a direction of propagation of the beam during detection.

Abstract: A polarization analyzing apparatus includes: a light source for generating optical pulses; a light dividing part; an electromagnetic wave radiation part; a collimation part; a polarizer part; a light analyzer part; a condenser part; an optical time-delay part; an electromagnetic wave detector part; and a calculation part which Fourier-transforms time-resolved waveforms obtained by time-resolving electrical signals of s- and p-polarized electromagnetic waves reflected from a sample, and calculates amplitude and phase information of the s- and p-polarized electromagnetic waves.

Abstract: A method and apparatus for characterizing and screening an array of material samples is disclosed. The apparatus includes a sample block having a plurality of regions for containing the material samples, a polarized light source to illuminate the materials, an analyzer having a polarization direction different than the polarization direction of the polarized light source, and a detector for analyzing changes in the intensity of the light beams. The light source, together with a polarizer, may include a plurality of light beams to simultaneously illuminate the entire array of materials with linearly polarized light so that characterization and screening can be performed in parallel. In addition, the materials in the sample block maybe subjected to different environmental conditions or mechanical stresses, and the detector analyzes the array as a function of the different environmental conditions or mechanical stresses.

Abstract: This invention provides methodology for the measurement of both low and high levels of scattered radiation produced by decorative and barrier coatings and plastics. Measurements of low levels are especially important for coatings used in automotive applications. The method is based on the illumination of the sample with radiation and collection of only the portion of the radiation scattered from the coating before, during and after the testing step and relating the optical signal from the tested portion of the sample material to the untested portion of the material and/or a standard. Through the practice of the invention, a large number of coating samples, as in an array, may be analyzed for their optical quality, principally haze, either after coating and curing, and/or after subjection of such coatings samples to elongation stresses, and/or abrasion testing, solvent exposure, hydrolytic stability testing, and temperature exposure.

Abstract: Provided are systems and methods using a Soleil-Babinet compensator (101) as a standard for calibrating birefringence measurement systems. Highly precise and repeatable calibration is accomplished by the method described here because, among other things, the inventive method accounts for variations of retardance across the surface of the Soleil-Babinet compensator (101). The calibration technique described here may be employed in birefringence measurement systems that have a variety of optical setups for measuring a range of retardation levels and at various frequencies of light sources.

Abstract: Measurements at multiple distinct polarization measurement states are taken to define the polarization state of an input, for example to calculate a Stokes vector. High accuracy and/or capability of frequent recalibration are needed, due to the sensitivity of measurement to retardation of the input signal. A multiple measurement technique takes a set of spatially and/or temporally distinct intensity measurements through distinct waveplates and polarizers. These can be optimized as to orientation and retardation using initial choices and also using tunable elements, especially controllable birefringence elements. A device matrix defines the response of the device at each of the measurement states. The matrix can be corrected using an iterative technique to revise the device matrix, potentially by automated recalibration.

Abstract: A fiber polarimeter has one or more oblique fiber Bragg gratings disposed one behind the other in a fiber. The fiber Bragg gratings couple out portions of a light wave input to the fiber depending on its polarization. For more than one fiber Bragg grating a wave plate is disposed in the fiber between consecutive fiber Bragg gratings. The portions of the light wave from the fiber Bragg grating(s) are detected to produce measurement data that is used to calculate four Stokes parameters for determining polarization, degree of polarization and/or power of the light wave.

Abstract: A polarization detector is described which contains a beam splitter, which disperses an incident light beam into partial beam paths. The partial beams pass though &lgr;/4 wafers and a cholesterol layer and impinge upon detectors. The polarization direction of the incident light beam can be measured by the polarization detector with the aid of the signal level of the detectors.

Abstract: An apparatus and a method for detecting an amount of depolarization of a linearly polarized beam transmitted by a birefringent medium in the direction of the optical axis thereof includes a first beam splitter for separating an on-axis portion of the linearly polarized beam into the orthogonal components, two photodetectors for detecting each component, a second beam splitter for separating an off-axis portion of the linearly polarized beam into the orthogonal components, the second beam splitter being disposed off-axis of the incident linearly polarized beam, a second set of photodetectors for detecting the components separated by the second beam splitter, and a subtracting device for subtracting the signals received by the second set of photodetectors from the respective signals received by the first two photodetectors.

Abstract: Disclosed is an odd bounce image rotating system with a sequence of an odd number of reflecting elements, such that a polarized electromagnetic beam caused to enter, reflectively interacts with the odd number of reflecting elements and exits along an essentially non-deviated, non-displaced locus, but with an azimuthally rotated polarization state. Application to, and methodology of application to set azimuthal angles of polarization in spectroscopic ellipsometer, polarimeter and the like systems is also disclosed.

Abstract: Stress-induced photoelastic birefringence compensates for intrinsic birefringence of cubic crystalline structures in deep ultraviolet (less than 200 nm) microlithographic imaging systems. Both the photoelastic birefringence and the intrinsic birefringence are expressed in a tensor format simplified by the symmetries of cubic crystalline structures. The stress-induced photoelastic birefringence can be sized to individually compensate for intrinsic birefringence exhibited in the same optical elements or preferably to collectively compensate for the cumulative effects of intrinsic birefringence in other optical elements in the lithography system.

Abstract: A method for automating measurement of an optical property of a sample includes selecting a measurement aperture around a reference point on the sample (38), generating a set of grid nodes that fall within the measurement aperture (68), calculating the radial distance of each node with respect to a reference point within the measurement aperture, and calculating the angular position of each node with respect to the vertical. The method also includes moving a light source (32) and a light detector along the vertical and rotating the sample to measurement positions in which the light source and the light detector are aligned with one of the nodes in the measurement aperture, and measuring the optical property at the measurement position by energizing the light source and interrogating the detector. The calculated radial distances and angular positions are used to control positioning of the light source and the light detector and rotation of the sample.

Abstract: Provided are systems and methods for precisely measuring birefringence properties of optical elements, especially those elements that are used in deep ultraviolet (DUV) wavelengths. The system includes two photoelastic modulators (PEM) (126, 128) located on opposite sides of the sample (136). Each PEM is operable for modulating the polarity of a light beam that passes though the sample. The system also includes a polarizer (124) associated with one PEM, an analyzer (130) associated with the other PEM, and a detector (132) for measuring the intensity of the light after it passes through the PEMs, polarizer, and analyzer. Described are techniques for determining birefringence properties across a wide range. For example, a dual-wavelength source light embodiment is provided for measuring relatively high levels of birefringence.

Abstract: A method and apparatus for sampling optical input signal is presented. The apparatus includes a split waveplate for spatially rotating polarization direction of a first portion (for example half, or 50 percent) of the input signal to a first rotated direction and spatially rotating polarization direction of a second portion (for example the other 50 percent) of the input signal to a second rotated direction orthogonal to the first rotated direction. The apparatus further includes a sum frequency generator, for example a PPLN crystal, aligned to the first rotated direction to sample the input signal. The rotation of the two halves of the input signal is achieved using a split half-waveplate.

Abstract: The present invention provides a method and system for determining three-dimensional refractive gradient index distribution. The method and system of the present invention determine inhomogeneity data and calculate index of refraction changes in three-dimensions (3D). The method and system provide 3D modeling of an optical object or system that determines the three-dimensional distribution of the refractive index in the object. In one embodiment, the optical object is a blank. In different embodiments, the optical system is more than one blank. In alternative embodiments, the optical system can be a projection optics system that can include optical components such as lenses, filters, plates, and prisms. The present invention also provides a method for selecting a plurality of preferred optical elements to assemble a composite optical system with predetermined parameters.

Abstract: A practical system and method for measuring waveplate retardation. The system employs a photoelastic modulator in an optical setup and provides high sensitivity. The analysis is particularly appropriate for quality-control testing of waveplates. The system is also adaptable for slightly varying the retardation provided by a waveplate (or any other retarder device) in a given optical setup. To this end, the waveplate position may be precisely altered to introduce correspondingly precise adjustments of the retardation values that the waveplate provides. The system is further refined to permit one to compensate for errors in the retardation measurements just mentioned. Such errors may be attributable to static birefringence present in the optical element of the photoelastic modulator that is incorporated in the system.

Abstract: The disclosure is directed to systems and methods for precisely measuring birefringence properties of large-format samples of optical elements. A gantry-like configuration is employed for precise movement of birefringence measurement system components relative to the sample. There is also provided an effective large-format sample holder that adequately supports the sample to prevent induced birefringence therein while still presenting a large area of the sample to the unhindered passage of light.

Abstract: A spectral ellipsometer includes a light incident optical system for focusing a incidence spot of polarized light of multi-wavelengths onto a sample surface. A detecting optical system receives the reflected light influenced by the sample surface so that the amount of change in an elliptical polarization will be characteristic of the sample surface. A spherical prism polarizer is employed in the light incident optical system having complimentary curved light incident and light exit surfaces to enable the focusing of the incident light so that each of the ray traces of the range of wavelengths are focused at the same position on the sample surface.

Abstract: A polarization imaging system and method are disclosed for measuring the magnitude and orientation of retardance in a sample. There are no moving parts and the invention is readily constructed as an imaging system that obtains polarization values at all point in a scene simultaneously. The system first takes an image that records the apparent slow axis orientation and the apparent retardance. However, the apparent retardance is indeterminate by m&lgr;, the wavelength of observation. By recording such images at two wavelengths, and taking note of both the apparent phase and the angular orientation of polarization interference in each of the two cases, the system is able to determine retardance values of 5&lgr; or more at every point without ambiguity. The actual slow axis orientation is determined as well. The determination of retardance value and axis orientation is independent for each point measured, and does not make use of spatial relationships or distributions within the sample.

Abstract: A method for automating measurement of an optical property of a sample includes selecting a measurement aperture around a reference point on the sample (38), generating a set of grid nodes that fall within the measurement aperture (68), calculating the radial distance of each node with respect to a reference point within the measurement aperture, and calculating the angular position of each node with respect to the vertical. The method also includes moving a light source (32) and a light detector along the vertical and rotating the sample to measurement positions in which the light source and the light detector are aligned with one of the nodes in the measurement aperture, and measuring the optical property at the measurement position by energizing the light source and interrogating the detector. The calculated radial distances and angular positions are used to control positioning of the light source and the light detector and rotation of the sample.