290 results about "Polarimeter" patented technology

A rotating compensator spectroscopic ellipsometer or polarimeter system having a source of a polychromatic beam of electromagnetic radiation, a polarizer, a stage for supporting a material system, an analyzer, a dispersive optics and a detector system which comprises a multiplicity of detector elements, the system being functionally present in an environmental control chamber and therefore suitable for application in wide spectral range, (for example, 130-1700 nm). Preferred compensator design involves a substantially achromatic multiple element compensator systems wherein multiple total internal reflections enter retardance into an entered beam of electromagnetic radiation, and the elements thereof 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.

A rotating compensator spectroscopic ellipsometer or polarimeter system having a source of a polychromatic beam of electromagnetic radiation, a polarizer, a stage for supporting a material system, an analyzer, a dispersive optics and a detector system which comprises a multiplicity of detector elements, the system being functionally present in an environmental control chamber and therefore suitable for application in wide spectral range, (for example, 130-1700 nm). Preferred compensator design involves a substantially achromatic multiple element compensator systems wherein multiple total internal reflections enter retardance into an entered beam of electromagnetic radiation, and the elements thereof 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.

A polarization camera includes a microlement polarizer that is situated in proximity to a focal plane array. The microlement polarizer is selectively scanned with respect to an optical image direct to the focal plane array, and an image processor stores a set of images associated with the scanning. Based on the stored images, a polarization image can be produced and displayed. A periodic microelement polarizer modulates the individual images of the set, and these images can be processed by filtering in the spatial frequency domain to isolate contributions associated with one or a combination of Stokes parameters. After filtering, Stokes parameter based images can be obtained by demodulating and inverse Fourier transforming the filtered frequency domain data.

Disclosed are improvements in ellipsometer and the like systems capable of operating in the Vacuum-Ultra-Violet (VUV) to Near Infrared (NIR) wavelength range, and methodology of use.

A light source unit irradiates a gas cell disposed in a measurement region with linearly polarized light in which the direction of travel is a z-axis direction and the vibration direction of an electric field is a y-axis direction. A polarimeter detects optical characteristics of light passing through the gas cell. A magnetic field generator applies an artificial magnetic field, capable of varying an x-axis component, a y-axis component, and a z-axis component, to the measurement region. A calculation control unit generates a plurality of artificial magnetic fields, calculates a magnetization value or a value corresponding to the magnetization value on the basis of the detection results of the polarimeter, and calculates an original magnetic field present in the measurement region, using an artificial magnetic field when the magnetization value or the value corresponding to the magnetization value satisfies a condition for external value.

A telecommunications optical fiber is secured against intrusion by detecting manipulation of the optical fiber prior to an intrusion event. This can be used in a non-locating system where the detection end is opposite the transmit end or in a locating system which uses Fresnel reflections and Rayleigh backscattering to the transmit end to detect and then locate the motion. The Rayleigh backscattering time sliced data can be stored in a register until an intrusion event is detected. The detection is carried out by a polarization detection system which includes an optical splitter which is manufactured in simplified form for economic construction. This uses a non-calibrated splitter and less than all four of the Stokes parameters. It can use a polarimeter type function limited to linear and circular polarization or two linear polarizers at 90 degrees.

An optical component for modulation of polarization, a Mueller polarimeter and ellipsometer containing such an optical component. The optical component modulates a linearly polarized incident beam and returns a modulated beam. It includes a coupled phase modulator which modulates the incident beam twice in succession, the two modulations having the same frequency of omega / 2pi, and a coupling system modifying the polarization state of the light between the two modulations. The ellipsometer includes the means for detection of a measurement beam returned by a sample, which receives the modulated beam, in addition to a processing unit. The means of detection include a polarimeter producing n measured quantities representing the polarization states of the beam, and the processing unit produces m values for each of these quantities by Fourier transform, with nxm>=16 and m>=4, providing simultaneous access to the sixteen components of the Mueller matrix of the sample.

A polarization-sensitive infrared image sensor (also termed a snapshot polarimeter) utilizing a 2-D array of polarizers to filter infrared light from a scene according to polarization, and a 2-D array of photodetectors (i.e. a focal plane array) to detect the filtered infrared light and generate polarization information which can be used to form a polarization-sensitive image of the scene. By forming each polarizer on an optical fiber in a fiber optic faceplate, the polarizers can be located facing a 2-D array of retarders to minimize diffraction effects of the infrared light. The optical fibers also guide the filtered infrared light to the photodetectors to reduce cross-talk in the polarization information. The polarizers can be formed as wire grid polarizers; and the retarders can be formed as subwavelength surface-relief gratings.

A multi-energy polarization imaging method consisting of a multi-fusion, dual-rotating retarder / multiple-energy complete Mueller matrix-based polarimeter and dual-energy capabilities, has been invented. The term multifusion describes the use of several imaging functions altogether such as polarimetric imaging, dual-energy subtraction, multifocal imaging and other. By substracting polarimetric parameters such as degree of polarization, degree of linear polarization, degree of circular polarization, respectively, obtained with interrogation light beams of wavelengths λ1 and λ2, he system, enhanced imaging is obtained. The system includes a light source for illuminating a target with a first quantity of light having a first wavelength and a second quantity of light having a second wavelength, the first and second wavelengths being different. A polarization-state generator generates a polarization state for each of the first and second quantities of light, and includes a first polarizer through which the first and second quantities of light are transmitted before entering a first waveplate. A polarization-state receiver evaluates a resulting polarization state of the first and second quantities of light following illumination of the target, the polarization-state receiver including a second waveplate through which the first and second quantittes of light are transmitted before entering a second polarizer. An optical image-capture device captures a first image of the target illuminated by the first quantity of light and a second image of the target illuminated by the second quantity of light. A processing unit assigns a weighting factor to at least one of the first and second images and evaluates a weighted difference between the first and second images to generate a multi-energy image of the target.

A telecommunications optical fiber is secured against intrusion by detecting manipulation of the optical fiber prior to an intrusion event. This can be used in a non-locating system where the detection end is opposite the transmit end or in a locating system which uses Fresnel reflections and Rayleigh backscattering to the transmit end to detect and then locate the motion. The Rayleigh backscattering time sliced data can be stored in a register until an intrusion event is detected. The detection is carried out by a polarization detection system which includes an optical splitter which is manufactured in simplified form for economic construction. This uses a non-calibrated splitter and less than all four of the Stokes parameters. It can use a polarimeter type function limited to linear and circular polarization or two linear polarizers at 90 degrees.

An apparatus (200) for determining fiber orientation parameters of a sheet of material during a production process includes a polarized radiation generating system (201, 202) operable for providing polarized radiation having a frequency of at least 1×108 Hz. The radiation is aligned to be incident on a sheet of material to be characterized (203). A polarimeter (204, 205) is aligned to receive the radiation transmitted by the sheet of material (203). A photodetector (206) is provided for measuring radiation received after polarization processing by the polarimeter. A processor (207) is coupled to the photodetector (206) for calculating Stokes parameters of the moving sheet (203) based upon intensities of the radiation received and determines at least one parameter relating to fiber orientation of the moving sheet based upon the Stokes parameters.

The present invention relates to a system and method for compensating for the effects of birefringence in a given sample and employs an optical birefringence analyzer to sense the real-time birefringence contributions and then provides a feedback signal to a compound electro-optical system that negates the birefringence contributions found in the given sample. The birefringence contribution vanishes, thus significantly reducing the main error component for polarimetric measurements.

A system for determining a new orientation and / or position of an object comprises a sky polarimeter configured to record image data of the sky, a signal processing unit, and logic configured to receive and store in memory the image data received from the sky polarimeter. The logic calculates the Stokes parameters (S0, S1, S2,), DoLP, and AoP from the image data, detects obscurants and filters the obscurants (such as clouds and trees) from the image data to produce a filtered image. The logic is further configured to find the Sun and zenith in the filtered image, and to determine the roll, pitch, yaw, latitude and longitude of the object using the filtered image. A method for determining a new position / orientation of an object comprises recording raw image data using a sky polarimeter, calculating S0, S1, S2, DoLP, and AoP from the image data, detecting obscurants and filtering the obscurants from the image data to produce a filtered image, obtaining last known position / orientation data of the object, finding the Sun and zenith in the filtered image, and determining the roll, pitch, yaw, latitude and longitude of the object using the filtered image.

Disclosed is a system for enabling easy sequential setting of different Angles-of-Incidence of a beam of electromagnetic radiation to a surface of a sample system, and to regression based methodology for evaluating and compensating the effects of the presence of electromagnetic beam intercepting angle-of-incidence changing systems, including where desired, parameterization of calibration parameters.

An optical measurement system for evaluating a reference sample, having at least a partially known composition, includes a reference ellipsometer and at least one non-contact optical measurement device. The ellipsometer includes a light generator, an analyzer, and a detector. The light generator generates a beam of quasi-monochromatic light of known wavelength and polarization, which is directed at a non-normal angle of incidence relative to the reference sample. The analyzer creates interference between S and P polarized components in the beam after interaction with the sample. The detector then measures the intensity of the beam, which a processor uses to determine the polarization state of the beam and, subsequently, an optical property of the reference sample. The processor then can calibrate an optical measurement device by comparing a measured optical parameter from the optical measurement device to the determined optical property from the reference ellipsometer.

A spectroscopic ellipsometer or polarimeter system having a source of a polychromatic beam of electromagnetic radiation, a polarizer, a stage for supporting a material system, an analyzer, a dispersive optics and a detector system which comprises a multiplicity of detector elements, there being apertures before the stage for supporting a material system, and thereafter, the system being present in an environmental control chamber.

An imaging polarimeter optics unit comprising: a first polarization-sensitive beam-splitter optic, a retarder, a second polarization-sensitive beam-splitter optic, and an analyzer, through which input light passes in sequence, wherein the retarder and polarization-sensitive beam-splitters cause the input light to have optical components that provide different information about the state of polarization of the input beam is provided.

Residual birefringence in optical fibers causes polarization mode dispersion (PMD). The invention compensates for this by using a polarization mode dispersion compensator and a polarimeter. The PMD compensator has a variable PMD that may be controlled. The output of the PMD compensator is monitored by a polarimeter. By dithering the wavelength of the optical signal, the polarimeter may provide an accurate measure of the PMD. A controller uses this measurement to control the PMD compensator. The PMD compensating scheme may also be incorporated in a wavelength division multiplexed system with each channel having its own PMD compensator. In addition, a control method may control any polarization mode dispersion compensator based on feedback from a polarimeter to reduce the PMD of the input signal. Instead of using a polarimeter, a Q detector may be used to monitor the output of the PMD compensator. The Q detector provides a measurement of the edge sharpness and, thereby, a measure of the PMD. The controller may use the Q value to control the PMD compensator.

A correlating polarimeter is provided for correlating a received waveform of a wideband electromagnetic signal with a predetermined waveform. The correlating polarimeter may include a first antenna for receiving an electromagnetic signal and a modulator interconnected with the first antenna for modulating the electromagnetic signal whereby a modulated electromagnetic signal results which contains a different polarization state for each frequency of the electromagnetic signal with the amplitude of each frequency component of the modulated electromagnetic signal being a function of the particular polarization state of each frequency component of the electromagnetic signal. The correlating polarimeter may also include a linear polarizer that may be configured to pass a first predetermined polarization of the modulated electromagnetic signal through a first output thereof, a first receiver for receiving and demodulating the electromagnetic signal from the linear polarizer and outputting a received waveform and a correlator operatively interconnected with the first receiver and being configured to compare the received waveform to a predetermined waveform and output a correlation indicator.

An imaging polarimeter optics unit comprising: a first polarization-sensitive beam-splitter optic, a retarder, a second polarization-sensitive beam-splitter optic, and an analyzer, through which input light passes in sequence, wherein the retarder and polarization-sensitive beam-splitters cause the input light to have optical components that provide different information about the state of polarization of the input beam is provided.

In one embodiment, the present invention is directed to a multi-energy polarization imaging method consisting of a multi-fusion, dual-rotating retarder / multiple-energy complete Mueller matrix-based polarimeter and dual-energy capabilities. By subtracting polarimetric parameters such as degree of polarization, degree of linear polarization, degree of circular polarization, respectively, obtained with interrogation light beams of wavelengths λ1, and λ2, the system of the present invention can obtain, in one embodiment, enhanced imaging.

A sample sequestering system which allows access to a subspace in a chamber encompassed generally enclosed space, for use in entering and removing a sample when the subspace is opened to atmosphere. Sufficient purge gas is flowed from within the generally enclosed space into the subspace discourage atmospheric contaminates from entering into the subspace. Contained within the generally enclosed space is a spectrophotometer, ellipsometer or polarimeter or the like system which operates at wavelengths, (eg. UV), which are adversely affected, (eg. absorbed), by typical atmospheric contents.

A system for the in vivo detection of the effects of AD in the interior of an eye. A scanning polarimeter, including a residual retardance canceling system and an improved anterior segment retardance compensator, produces an optical analysis signal representing the birefringence of the retinal nerve fiber layer (RNFL) structures of the eye. The birefringence data is more accurate because of compensation for anterior segment birefringence and residual birefringence of optical components, such as, for example, the beam splitters, lenses, scanners and retarders. An electrical analysis signal representing a large (20 by 40 degrees) retardance map is produced and evaluated by an artificial neural network to produce an analysis classification signal representing the contribution of Alzheimer's disease to the birefringence of the retinal layer corresponding to the relationship of the electrical analysis signal to an analysis signal database.

Low aberration relay systems modified to perform as spatial filters in rotating compensator ellipsometer, polarimeter and the like systems.

A method to monitor the state of polarization incident on the photomask in projection printing is presented. The method includes a series of phase-shifting mask patterns that take advantage of high NA effects to create a signal dependent on only one incident polarization component. The patterns exist in two embodiments: a Radial Phase Grating (RPG) and Proximity Effect Polarization Analyzers (PEPA). The PEPAs are derived from basic principles and are theoretically the most sensitive patterns to polarization. A polarimeter is then constructed of six patterns of either embodiment that, when properly calibrated, is sufficient to measure the Stokes parameters of the incident illumination. A test reticle design is proposed, consisting of multiple polarimeters with an array of pinholes on the backside of the photomask. This technique is able to monitor any arbitrary illumination scheme for a particular tool. Calibration of the test mask is required. However, proper calibration is likely to enable accurate full pupil polarization characterization, even when severe mask topography effects and reasonable maskmaking limitations are considered.

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.

A telecommunications optical fiber is secured against intrusion by detecting manipulation of the optical fiber prior to an intrusion event. This can be used in a non-locating system where the detection end is opposite the transmit end or in a locating system which uses Fresnel reflections and Rayleigh backscattering to the transmit end to detect and then locate the motion. The Rayleigh backscattering time sliced data can be stored in a register until an intrusion event is detected. The detection is carried out by a polarization detection system which includes an optical splitter which is manufactured in simplified form for economic construction. This uses a non-calibrated splitter and less than all four of the Stokes parameters. It can use a polarimeter type function limited to linear and circular polarization or two linear polarizers at 90 degrees.

A polarimeter includes a multi-wavelength source for generating electromagnetic waves having at least two different wavelengths, means for separating electromagnetic waves, the electromagnetic waves including electromagnetic waves generated by the multi-wavelength source and electromagnetic waves received from a sample contacted by the electromagnetic waves generated by the multi-wavelength source, a fixed waveplate, wherein the fixed waveplate is configured to convert one polarization state to multiple polarization states that allow for calculations of linear and circular polarization components of the electromagnetic waves, a free space coupler, a beam splitter, and more than one detector. The polarimeter may be used in a method for high-speed measurement of linear and circular polarization components of electromagnetic waves.

By making combined interferometric and polarimetric measurements on a device under test, the relative phase uncertainty in device characterizations performed with a polarimeter or polarization analyzer alone is removed. This allows determination of the group delay to within a constant offset and the chromatic dispersion of the device under test.

The present invention provides a method and apparatus for improving the signal to noise ratio, the contrast and the resolution in images recorded using an optical imaging system which produces a spatially resolved image. The method is based on the incorporation of a polarimeter into the setup and polarization calculations to produce better images. After calculating the spatially resolved Mueller matrix of a sample, images for incident light with different states of polarization were reconstructed. In a shorter method, only a polarization generator is used and the first row of the Mueller matrix is calculated. In each method, both the best and the worst images were computed. In both reflection and transmission microscope and Macroscope and ophthalmoscope modes, the best images are better than any of the original images recorded. In contrast, the worst images are poorer. This technique is useful in different fields such as confocal microscopy, Macroscopy and retinal imaging.