20864 results about "Optical polarization" patented technology

An endoscope assembly with a main imaging device and a first light source is configured to provide a forward view of a body cavity, and further includes a detachable imaging device with an attachment member engageable with the distal end region of the endoscope, a linking member connected to the attachment member, and an imaging element with a second light source, wherein the detachable imaging device provides a retrograde view of the body cavity and the main imaging device. Light interference is reduced by using polarizing filters or by alternating the on / off state of the main imaging device, the first light source, the imaging element and the second light source so that the main imaging device and first light source are on when the imaging element and second light source are off and the main imaging device and first light source are off when the imaging element and second light source are on.

A radial transverse electric polarizer device is provided. The device includes a first layer of material having a first refractive index, a second layer of material having a second refractive index, and a plurality of elongated elements azimuthally and periodically spaced apart, and disposed between the first layer and the second layer. The plurality of elongated elements interact with electromagnetic waves of radiation to transmit transverse electric polarization of electromagnetic waves of radiation. One aspect of the invention is, for example, to use such polarizer device in a lithographic projection apparatus to increase imaging resolution. Another aspect is to provide a device manufacturing method including polarizing a beam of radiation in a transverse electric polarization.

Alignment accuracy between two or more patterned layers is measured using a metrology target comprising substantially overlapping diffraction gratings formed in a test area of the layers being tested. An optical instrument illuminates all or part of the target area and measures the optical response. The instrument can measure transmission, reflectance, and / or ellipsometric parameters as a function of wavelength, polar angle of incidence, azimuthal angle of incidence, and / or polarization of the illumination and detected light. Overlay error or offset between those layers containing the test gratings is determined by a processor programmed to calculate an optical response for a set of parameters that include overlay error, using a model that accounts for diffraction by the gratings and interaction of the gratings with each others' diffracted field. The model parameters might also take account of manufactured asymmetries. The calculation may involve interpolation of pre-computed entries from a database accessible to the processor. The calculated and measured responses are iteratively compared and the model parameters changed to minimize the difference.

Polarization mode dispersion in an optical signal transmitted through a waveguide of a communications system is compensated by separating the dispersed signal into components corresponding to principal polarization states. The components are delayed by respective delays differing by a delay increment which is controlled to correspond to the dispersion delay and the delayed components are recombined to provide a dispersion compensated optical output signal. Each of the delays is provided by an chirped Bragg reflector forming part of a delay line, the Bragg reflectors comprising optical fibres with chirped intracore index gratings. Transducers or temperature controllers acting on one of the fibres allows dimensional control of the grating periodicity such that the position of Bragg reflection is variable. Wavelength division multiplexed optical signals are compensated using sampled gratings which allow a common Bragg reflection position for each wavelength.

An overlay measurement apparatus has a polarized light source for illuminating a sample with a polarized light beam and an optical system to capture light that is scattered by the sample. The optical system includes a polarizer for transmitting an orthogonal polarization component that is orthogonal to a polarization direction of the polarized light beam. A detector measures intensity of the orthogonal polarization component. A processing unitise connected to the detector, and is arranged to process the orthogonal polarization component for overlay metrology measurement using asymmetry data derived from the orthogonal polarization component.

A network for power transmission to a receiver which converts the power into current includes a first node for transmitting power with circularly polarized waves in a first area. The network includes a second node for transmitting power with circularly polarized waves in a second area. Alternatively, elliptically polarized waves or dual polarized waves are used or different frequencies are used or different polarizations are used or different polarization vectors are used. Also disclosed is a method for power transmission to a receiver which converts the power into current.

An illumination optical system for, when installed in an exposure system, realizing a suitable illumination condition by varying the polarized state of the illumination light according to the pattern characteristics of the mask while suppressing the loss of the intensity of the light. The illumination optical system has a light source unit for supplying a linearly polarized light for illuminating surfaces to be illuminated therewith, and a polarized state changing device for changing the polarized state of the illuminating light from a predetermined polarized state to a nonpolarized state and vice versa. The polarized state changing device is arranged in the optical path between the light source unit and the surfaces to be illuminated. The polarized state changing device can be removed from the illumination optical path and has a depolarizer for selectively depolarizing the incident linearly polarized light.

An apparatus generates femtosecond pulses from laser amplifiers by nonlinear frequency conversion. The implementation of nonlinear frequency-conversion allows the design of highly nonlinear amplifiers at a signal wavelength (SW), while still preserving a high-quality pulse at an approximately frequency-doubled wavelength (FDW). Nonlinear frequency-conversion also allows for limited wavelength tuning of the FDW. As an example, the output from a nonlinear fiber amplifier is frequency-converted. By controlling the polarization state in the nonlinear fiber amplifier and by operating in the soliton-supporting dispersion regime of the host glass, an efficient nonlinear pulse compression for the SW is obtained. The generated pulse width is optimized by utilizing soliton compression in the presence of the Raman-self-frequency shift in the nonlinear fiber amplifier at the SW. High-power pulses are obtained by employing fiber amplifiers with large core-diameters. The efficiency of the nonlinear fiber amplifier is optimized by using a double clad fiber (i.e., a fiber with a double-step refractive index profile) and by pumping light directly into the inner core of this fiber. Periodically poled LiNbO3 (PPLN) is used for efficient conversion of the SW to a FDW. The quality of the pulses at the FDW can further be improved by nonlinear frequency conversion of the compressed and Raman-shifted signal pulses at the SW. The use of Raman-shifting further increases the tuning range at the FDW. For applications in confocal microscopy, a special linear fiber amplifier is used.

An Optical Coherence Tomography (OCT) device irradiates a biological tissue with low coherence light, obtains a high resolution tomogram of the inside of the tissue by low-coherent interference with scattered light from the tissue, and is provided with an optical probe which includes an optical fiber having a flexible and thin insertion part for introducing the low coherent light. When the optical probe is inserted into a blood vessel or a patient's body cavity, the OCT enables the doctor to observe a high resolution tomogram. In a optical probe, generally, a fluctuation of a birefringence occurs depending on a bend of the optical fiber, and this an interference contrast varies depending on the condition of the insertion. The OCT of the present invention is provided with polarization compensation means such as a Faraday rotator on the side of the light emission of the optical probe, so that the OCT can obtain the stabilized interference output regardless of the state of the bend.

An apparatus includes a first section operable to detect polarization-sensitive radiation emitted by an object, and a second section operable to determine a Jones matrix based on information obtained by the first section from the polarization-sensitive radiation. The second section thereafter transforms the Jones matrix into a Mueller matrix, the Mueller matrix being representative of properties of the object.

Optical gain of a nonpolar or semipolar Group-III nitride diode laser is controlled by orienting an axis of light propagation in relation to an optical polarization direction or crystallographic orientation of the diode laser. The axis of light propagation is substantially perpendicular to the mirror facets of the diode laser, and the optical polarization direction is determined by the crystallographic orientation of the diode laser. To maximize optical gain, the axis of light propagation is oriented substantially perpendicular to the optical polarization direction or crystallographic orientation.

A beam steering apparatus includes a first beam steering stage and at least a second beam steering stage arranged in-line with the first beam steering stage. The first beam steering stage includes a first polarization grating comprising a uniaxial birefringent material having a first periodic director pattern, and the second beam steering stage includes a second polarization grating comprising a uniaxial birefringent material having a second periodic director pattern. In nonmechanical embodiments, a polarization selector may be arranged to provide a circularly polarized input beam incident on the first polarization grating. In mechanical embodiments, at least one of the first polarization grating and the second polarization grating may be operable to be independently rotated about an azimuth thereof. Related methods of operation are also discussed.

A liquid crystal device including a front electrode layer, rear electrode layer, a liquid crystal material located between the front electrode layer and the rear electrode layer. A polarizer is located between the liquid crystal material and the front electrode layer and changing an electrical potential between the rear electrode layer and the front electrode layer modifies portions of the liquid crystal material to change the polarization of the light incident thereon. A plurality of light sensitive elements are located together with the rear electrode layer and a processor determines the position of at least one of the plurality of light sensitive elements that has been inhibited from sensing ambient light.

Alignment accuracy between two or more patterned layers is measured using a metrology target comprising substantially overlapping diffraction gratings formed in a test area of the layers being tested. An optical instrument illuminates all or part of the target area and measures the optical response. The instrument can measure transmission, reflectance, and / or ellipsometric parameters as a function of wavelength, polar angle of incidence, azimuthal angle of incidence, and / or polarization of the illumination and detected light. Overlay error or offset between those layers containing the test gratings is determined by a processor programmed to calculate an optical response for a set of parameters that include overlay error, using a model that accounts for diffraction by the gratings and interaction of the gratings with each others' diffracted field. The model parameters might also take account of manufactured asymmetries. The calculation may involve interpolation of pre-computed entries from a database accessible to the processor. The calculated and measured responses are iteratively compared and the model parameters changed to minimize the difference.

A collimating image-forming apparatus comprising a first linear polarizer is disclosed. A first quarter-wave plate is disposed adjacent the first polarizer and has its fast and slow axes at substantially 45° to the plane of polarization of the first polarizer. The apparatus further comprises a beam-splitting curved mirror having a convex surface adjacent the first polarizer and facing towards the first quarter-wave plate, a second quarter-wave plate adjacent the concave side of the curved mirror, the second quarter-wave plate having its having its fast and slow axes oriented with respect to the corresponding axes of the first quarter-wave plate at angles substantially equal to a first integral multiple of 90°, and a reflective-transmissive polarizing member adjacent the second quarter-wave plate. A second linear polarizer is adjacent the reflective-transmissive polarizing member, the second linear polarizer having its plane of polarization oriented with respect to the plane of polarization of the first linear polarizer at an angle substantially equal to a second integral multiple of 90°, both of the multiples being even or both being odd.

There is provided an optical device, including a light waves-transmitting substrate having two major surfaces and edges, optical means for coupling light into the substrate by total internal reflection, and a plurality of partially reflecting surfaces (22a, 22b) carried by the substrate wherein the partially reflecting surfaces (22a, 22b) are parallel to each other and are not parallel to any of the edges of the substrate, and wherein one or more of the partially reflecting surfaces (22a, 22b) is an anisotropic surface.

A head-up display includes a projection system and a window having a target area where a reflective polarizer is positioned to reflect light from the projection system to a viewing area. Light from the projection system is p-polarized and strikes exposed window surface(s) at an acute angle to reduce or eliminate multiple or “ghost” images. The acute angle is closely matched to a Brewster angle of the exposed window surface(s). The reflective polarizer includes a multilayer stack with refractive indices of individual layers chosen to reflect p-polarized light substantially more than s-polarized light over a wide angular range that includes the acute angle. The reflective polarizer also can reflect infrared light to reduce cabin heating from solar radiation.

The purpose of the invention is to provide a light guide of a variety of forms having a uniform distribution of brightness in the plane and a planer light source device for a liquid crystal display device which uses such light guide. The light guide comprises a first surface which is a surface to which a natural polarization light is incident and a second surface other than the first surface which is an exit surface of a specific polarization light into which, said natural polarization light is modulated, wherein;said light guide has an interface of two materials of different indices of refraction oriented at an angle of thetaB+ / -alpha degrees relative to the primary propagation direction of said incident light, said thetaB being an angle satisfying Brewster's condition, more than two orientations of said interface exist in a single light guide, and the difference between the indices of refraction of the two materials of different indices of refraction is between 0.001 and 1.0. thetaB is typically about 45 degrees. The light guide comprises a first transparent member having a plurality of upwardly convex right angle isosceles triangles on a first surface thereof and a first index of refraction and a second transparent member having a plurality of downwardly convex right angle isosceles triangles on a second surface thereof and a second index of refraction, and said first surface and said second surface contact each other.

Antenna apparatuses and related antenna units that include antenna selection based on orientation are disclosed. Related methods and distributed antenna systems are also disclosed. Antenna selection is provided between two or more antennas disposed in different polarization orientations according to orientation of the antenna unit in which the antennas are included. The antenna(s) oriented most closely to perpendicular to the ground in one embodiment may be selected for use in wireless communications with wireless client devices. In this manner, the antenna(s) employed in wireless communications is likely to be the closest in polarization to the polarization of wireless client device antennas. Otherwise, an unacceptable reduction in communications link quality with the wireless client devices may occur.

Anisotropic film laminates for use in image-preserving reflectors such as rearview automotive mirror assemblies, and related methods of fabrication. A film may comprise an anisotropic layer such as a light-polarizing layer and other functional layers. The film having controlled water content is heated under omnidirectional pressure and vacuum to a temperature substantially equal to or above a lower limit of a glass-transition temperature range of the film so as to be laminated to a substrate. The laminate is configured as part of a mirror structure so as to increase contrast of light produced by a light source positioned behind the mirror structure and transmitted through the mirror structure towards a viewer. The mirror structure is devoid of any extended distortion and is characterized by SW and LW values less than 3, more preferably less than 2, and most preferably less than 1.

In a polarization maintaining multi-core optical fiber according to the present invention, structural birefringence is generated since an elliptic core is applied. In addition, each core is arranged so that a direction of a line connecting between centers of the nearest cores and a long axis direction of a field distribution in each core may be different from each other, and thereby, overlap of field distributions between the nearest cores is reduced. As a result, a crosstalk among cores is reduced.

An achromatic polarization switch (APS) acts on linear polarized light to provide orthogonal polarized output states over a range of visible wavelengths. In a first switching state, the APS is operable to pass light of a first polarization state therethrough. In a second switching state, the APS is operable to transform light passing therethrough to a substantially orthogonal second polarization state. Used in conjunction with orthogonal analyzing eyewear, left and right eye images are time-sequentially modulated in orthogonal polarization states by the APS to yield a stereoscopic 3D image sensation.

An endoscope includes an imaging device, a first polarizing filter disposed in front of the imaging device, a light source, and a second polarizing filter disposed in front of the light source. The planes of polarization of the first and second polarizing filters are at a substantially 90° angle.

Various embodiments disclosed herein relate to optical elements comprising an at least partial coating having a first state and a second state connected to at least a portion of a substrate, the at least partial coating being adapted to switch from the first state to the second state in response to at least actinic radiation, to revert back to the first state in response to thermal energy, and to linearly polarize at least transmitted radiation in at least one of the first state and the second state. Other embodiments relate to optical elements comprising a substrate and at least one at least partially aligned photochromic-dichroic compound connected to at least a portion of the substrate and having an average absorption ratio greater than 2.3 in the activated state as determined according to CELL METHOD. Still other embodiments relate to security devices, liquid crystal cells and methods of making the same.

An edge lit illumination system is directed to providing backlighting utilizing a luminescent impregnated lightguide. The apparatus includes an LED radiation source providing a first radiation and a lightguide optically coupled to the LED radiation source including a luminescent material embedded or coated on an output surface of the lightguide designed to absorb the first radiation, and emit one or more radiations. The illumination system may further include additional optical components such as reflective layers, for directing radiation striking the back surfaces of the light guide back into the lightguide, as well as diffusion layers, UV reflectors, and polarizers.

An imaging system, comprising a broadband unpolarized white light source (81), a polarization converter system for converting polarization axes of unpolarized white light into a substantially single polarization axis, to produce a beam of polarized light, a selective polarization filter (82), adapted to selectively rotate a polarization axis of a selected spectral band of light of the with respect to remaining polarized light based on a control signal (119), a polarized beam splitter (84), for separating light having a the substantially single polarization axis from light having a rotated polarization axis, a pair of electro-optic spatial light modulators (86, 89), disposed along a path of light within the spectral band and a path of remaining light outside the spectral band, respectively, and being adapted to modulate an image therein, and a polarized beam splitter (88), for recombining modulated light from the pair of light modulators. In a preferred embodiment, the selective polarization filter (82, 72) is divided into a plurality of regions (70, 71), each adapted to independently and selectively rotate a polarization axis of a selected spectral band of light of the with respect to remaining polarized light.

The present invention relates in general to systems for and methods of three-dimensional viewing of displays and projections. One embodiment two layers (50, 90) are uniform polarizing filters and a birefringent layer with individually switchable elements (60) is sandwiched between them. Together these layers (50, 60, 90) constitute a parallax layer (40). This parallax layer (40) is located at a certain distance from a display (10). This placement, and the existence of opaque areas on the parallax layer (40) which permits to a viewer see a three-dimensional image. The individual elements (601–615) of the birefringent layer (60) are controlled by a control element (80), which is in communication with a head-tracking sensor (85). This allows the individual elements (601–615) of the birefringent layer (60) to be selectively turned on and off according to the position of the viewer's head.

A polarization-maintaining optical fiber includes a core region and a cladding region formed around the core region. The cladding region has a refractive index lower than a refractive index of the core region. A refractive index profile of the core region is either one of a step shaped or a concave shaped. The cladding region includes two holes formed in such a manner that a shortest distance from the core region is virtually zero at locations in opposite to each other across the core region.

Systems, arrangements and methods for separating an electromagnetic radiation and obtaining information for a sample using an electromagnetic radiation are provided. In particular, the electromagnetic radiation can be separated into at least one first portion and at least one second portion according to at least one polarization and at least one wave-length of the electromagnetic radiation. The first and second separated portions may be simultaneously detected. Further, a first radiation can be obtained from the sample and a second radiation may be obtained from a reference, and the first and second radiations may be combined to form a further radiation, with the first and second radiations being associated with the electro-magnetic radiation. The information is provided as a function of first and second portions of the further radiations that have been previously separated and can be analyzed to extract birefringent information characterizing the sample.

There is provided in one embodiment an optical reader having an image sensor array. In one embodiment, the image sensor array can include a first subset of pixels and a second subset of pixels. The first subset of pixels can be devoid of light polarizing filter elements, and the second subset of pixels can be light polarizing pixels including light polarizing filter elements. An optical reader can be configured to selectively read out image data from an image sensor array's light polarizing pixels.