The University of Arizona

The University of Alabama

Jds Uniphase Corporation

US Government As Represented by the Secretary of the Army

United States of America As Represented by the Secretary of the Air Force

United States of America As Represented by the Administrator of Nasa

Russell A Chipman

Matthew H Smith

Stanley K Pau

Kurt R Denninghoff

Lloyd W Hillman

Thomas E Minnich

Karlton Crabtree

Robert G Waarts

Massimo Martinelli

Dennis H Goldstein

Richard J Kreis

J Scott Tyo

Wei-Liang Hsu

Lester D Strauch, Iii

Stephen Charles McClain

Steven A Macenka

David Chenault

Brian J Daugherty

Bradley M Ratliff

Compound dichroic polarizers (CDPs) include multiple component dichroic polarizers based on different dichroic dyes and oriented to have different eigenpolarization directions. The component dichroic polarizers can be fixed to each other or to a substrate such as an eyeglass lens. Selection of eigenpolarization orientation and spectrum in a CDP permits color encoding of different SOPs.

Compound dichroic polarizers with wavelength dependent transmission axes

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.

Microgrid imaging polarimeters with frequency domain reconstruction

Disclosed herein is a method of determining the near angle scattering of a sample reflective surface comprising the steps of: a) splitting a beam of light having a coherence length of greater than or equal to about 2 meters into a sample beam and a reference beam; b) frequency shifting both the sample beam and the reference beam to produce a fixed beat frequency between the sample beam and the reference beam; c) directing the sample beam through a focusing lens and onto the sample reflective surface, d) reflecting the sample beam from the sample reflective surface through a detection restriction disposed on a movable stage; e) recombining the sample beam with the reference beam to form a recombined beam, followed by f) directing the recombined beam to a detector and performing heterodyne analysis on the recombined beam to measure the near-angle scattering of the sample reflective surface, wherein the position of the detection restriction relative to the sample beam is varied to occlude at least a portion of the sample beam to measure the near-angle scattering of the sample reflective surface. An apparatus according to the above method is also disclosed.

Method and apparatus for measuring near-angle scattering of mirror coatings

A cube corner retro-reflector that includes three mutually perpendicular reflecting planes arranged in a pyramidal configuration, wherein at least one of the reflecting planes has a non-isotropic surface causing a polarization state of a ray exiting the cube corner retro-reflector to be orthogonal or substantively orthogonal to a polarization state of a ray entering the cube corner retro-reflector for all linear polarization orientations.

Polarization coupling cube-corner retro-reflectors

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.

Advanced polarization imaging method, apparatus, and computer program product for retinal imaging, liquid crystal testing, active remote sensing, and other applications

A radiation source has a radiation-emitter assembly disposed, at least in part, in a first compartment of a housing. A lens system is disposed in a second compartment of the housing so that the lens system is optically coupled to the radiation-emitter assembly. A mirror is disposed in a third compartment of the housing so that the mirror is optically coupled to the lens system. A filter and a conduit are disposed in a fourth compartment of the housing so that the filter and an aperture provided by the conduit are optically coupled to the mirror. Radiation exits the radiation source through the aperture.

Radiation source with self-aligning optics

The invention relates to the monitoring of polarization mode dispersion (PMD) using heterodyne detection for providing PMD compensation in optical networks, and an apparatus for monitoring PMD. In the present invention, a broadband PMD monitor is disclosed based on heterodyne detection with a tunable laser source which can be fed to a compensator such as an add/drop or other wavelength switch and polarization dependent attenuation means. A signal from a local oscillator is combined with an optical signal and the beat frequency amplitude and phase is analyzed for two orthogonal polarization states simultaneously to obtain a state of polarization. By averaging a plurality of polarization states within a channel, PMD can be estimated for compensation.

Method and apparatus for polarization mode dispersion monitoring in a multiple wavelength optical system

Polarization controlling elements equivalent to quarter and half waveplates are constructed from sequences of variable retarder plates having fixed retardation axes. An endless polarization control algorithm is provided.

Polarization controller

An improved optical scanning spectroscopic method and apparatus is provided that alternately scans the posterior portion of an eye with laser signals emitted by different ones of a plurality of lasers such that a data frame can be constructed that includes interlaced portions formed from signals returning from the posterior portion of the eye in response to illumination by laser signals emitted by different ones of the plurality of lasers. As such, the same data frame includes data attributable to the reflection of laser signals from each of the plurality of lasers even though the subject's eye is not subjected to simultaneous illumination by each of the lasers, thereby protecting the subject's eye. According to one further aspect of the invention, the optical scanning spectroscopic method and apparatus can illuminate the posterior portion of the subject's eye in response to a trigger at a predetermined point in the cardiac cycle of the subject such that the resulting data frame relates to at least a predetermined portion of the cardiac cycle of the subject, thereby permitting a detailed analysis of one or more phases of the cardiac cycle of the subject.

Optical scanning spectroscopic apparatus and associated method

The method and apparatus for measuring the transmittance of blood within a retinal vessel detects the intensity of light reflected from illuminated portions of an eye, including the retinal vessel and background fundus, and adjusts the corresponding intensity signals to compensate for reflections from the retinal vessel. In particular, the transmittance measuring method and apparatus constructs an intensity profile function based upon the intensity signals. As a result, the intensity profile function approximates the intensity of light transmitted through the retinal vessel as a function of retinal vessel position. During the construction of the intensity profile function, the transmittance measuring method and apparatus can compensate for at least some of the reflections of light from the retinal vessel which occurred prior to propagation of the light through the retinal vessel, thereby increasing the accuracy with which the transmittance of blood within a retinal vessel is measured. In addition, the transmittance measuring method and apparatus can compensate for the finite point spread function of the light with which the eye is illuminated in order to further increase the resulting measurement accuracy.

Method and apparatus for accurately measuring the transmittance of blood

The method and apparatus for measuring the oxygen saturation of blood within a retinal vessel illuminates the retinal vessel with light having a combination of wavelengths selected to reduce the error in the measured blood oxygen saturation. The oxygen saturation measuring method and apparatus illuminates a retinal vessel with light having the selected combination of wavelengths. For example, the oxygen saturation measuring method and apparatus can illuminate the retinal vessel with light having a first wavelength between 460 nm and 503 nm, a second wavelength between 600 nm, and 770 nm and a third wavelength between 770 nm and 1000 nm. The oxygen saturation measuring method and apparatus then measures the transmittance of the blood within the retinal vessel in response to the illumination at each of the selected wavelengths. Based upon the respective transmittances of the blood within the retinal vessel that are measured at each of the selected wavelengths, the oxygen saturation measuring method and apparatus determines the oxygen saturation of the blood within the retinal vessel. By appropriately selecting the combination of wavelengths with which the retinal vessel is illuminated, the corresponding error in the measured blood oxygen saturation can be reduced.

Method and apparatus for measuring blood oxygen saturation within a

An infrared spectropolarimeter system for making spectroscopic measurements of electro-optic properties of materials over a large wavelength range in the infrared is described which comprises in combination a spectrometer having a sample region for receiving a sample for making spectroscopic measurements thereon and a source of light for providing a sample beam of selected wavelength for projection through the sample region, the sample region defined between a first focusing element for selectively focusing the sample beam within the sample region and a second focusing element for collimating the sample beam and providing an output beam for analysis, first and second polarizers between the focusing elements with the sample region therebetween for selectively polarizing the sample beam, first and second rotatable optical retarders between the polarizers with the sample region therebetween for selectively retarding one linear polarization component with respect to the orthogonal component of the sample beam, and a detector for analyzing the output beam.

Infrared spectropolarimeter

An infrared achromatic waveplate structure having a cadmium sulfide (CdS) plate and a cadmium selenide (CdSe) plate aligned with each other so that the fast axis of the plates are perpendicular to each other, this structure provides a desired retardance of a first orthogonal polarization component with respect to a second orthogonal polarization component of an incident light beam. The thickness of the plates are in a ratio between 0.8:1 and 0.9:1 (CdSe:CdS), an achromatic response with a substantially constant retardance is provided in a wavelength range from 3 to 11 microns. A desired amount of retardance is available by adjusting the thickness of the two plates as long as the ratio of the thicknesses is maintained within the recited value. In particular a quarter wave net retardance of an incident light beam operating between 3 and 11 microns is provided when the cadmium sulfide plate is 1.25 millimeters and the cadmium selenide plate is 1.0666 millimeters.

Growing community of inventors

Madison, AL, United States of America

Russell A Chipman