328 results about "Polarization sensitive" patented technology

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.

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.

Arrangement, system and method for a polarization effect for a interferometric signal received from sample in an optical coherence tomography (“OCT”) system are provided. In particular, an interferometric information associated with the sample and a reference can be received. The interferometric information is then processed thereby reducing a polarization effect created by a detection section of the OCT system on the interferometric signal. Then, an amount of a diattenuation of the sample is determined. The interferometric information can be provided at least partially along at least one optical fiber which is provided in optical communication with and upstream from a polarization separating arrangement. In another exemplary embodiment of the present invention, apparatus and method are provided for transmitting electromagnetic radiation to the sample. For example, at least one first arrangement can be provided which is configured to provide at least one first electromagnetic radiation. A frequency of radiation provided by the first arrangement can vary over time. At least one polarization modulating second arrangement can be provided which is configured to control a polarization state of at least one first electromagnetic radiation so as to produce at least one second electromagnetic radiation. Further, at least one third arrangement can be provided which is configured to receive the second electro-magnetic radiation, and provide at least one third electromagnetic radiation to the sample and at least one fourth electromagnetic radiation to a reference. The third and fourth electromagnetic radiations may be associated with the second electromagnetic radiation.

Optical coherence tomography (OCT) probe and system designs are disclosed that minimize the effects of mechanical movement and strain to the probe to the OCT analysis. It also concerns optical designs that are robust against noise from the OCT laser source. Also integrated OCT system-probes are included that yield compact and robust electro-opto-mechanical systems along with polarization sensitive OCT systems.

Arrangements and methods are provided for obtaining data associated with a sample. For example, at least one first electro-magnetic radiation can be provided to a sample and at least one second electro-magnetic radiation can be provided to a reference (e.g., a non-reflective reference). A frequency of such radiation(s) can repetitively vary over time with a first characteristic period. In addition, a polarization state of the first electro-magnetic radiation, the second electro-magnetic radiation, a third electro-magnetic radiation (associated with the first radiation) or a fourth electro-magnetic radiation (associated with the second radiation) can repetitively vary over time with a second characteristic period which is shorter than the first period. The data for imaging at least one portion of the sample can be provided as a function of the polarization state. In addition or alternatively, the third and fourth electro-magnetic radiations can be combined so as to determine an axial reflectance profile of at least one portion of the sample.

An apparatus and method to determine the surface orientation of objects in a field of view is provided by utilizing an array of polarizers and a means for microscanning an image of the objects over the polarizer array. In the preferred embodiment, a sequence of three image frames is captured using a focal plane array of photodetectors. Between frames the image is displaced by a distance equal to a polarizer array element. By combining the signals recorded in the three image frames, the intensity, percent of linear polarization, and angle of the polarization plane can be determined for radiation from each point on the object. The intensity can be used to determine the temperature at a corresponding point on the object. The percent of linear polarization and angle of the polarization plane can be used to determine the surface orientation at a corresponding point on the object. Surface orientation data from different points on the object can be combined to determine the object's shape and pose. Images of the Stokes parameters can be captured and viewed at video frequency. In an alternative embodiment, multi-spectral images can be captured for objects with point source resolution. Potential applications are in robotic vision, machine vision, computer vision, remote sensing, and infrared missile seekers. Other applications are detection and recognition of objects, automatic object recognition, and surveillance. This method of sensing is potentially useful in autonomous navigation and obstacle avoidance systems in automobiles and automated manufacturing and quality control systems.

Disclosed is an imaging directional backlight polarization recovery apparatus including an imaging directional backlight with at least a polarization sensitive reflection component with optional polarization transformation and redirection elements. Viewing windows may be formed through imaging individual light sources and hence defines the relative positions of system elements and ray paths. The base imaging directional backlight systems provide substantially unpolarized light primarily for the illumination of liquid crystal displays (LCDs) resulting in at least 50% loss in light output when using a conventional sheet polarizer as input to the display. The invention herein introduces a polarization sensitive reflecting element to separate desired and undesired polarization states for the purposes of transformation and redirection of the reflected light for usable illumination. Polarization transformation and redirection can be provided by additional components such as retarder films and specular mirror surfaces.

A polarization grating comprising a polarization sensitive photo-alignment layer (2) and a liquid crystal composition (3) arranged on said photo-alignment layer is provided. An alignment pattern, corresponding to the polarization pattern of a hologram, is recorded in the photo-alignment layer, and the liquid crystal composition is aligned on the photo-alignment layer. As the origin for the alignment of the liquid crystal composition is a polarization hologram recorded in a photo-alignment layer, an essentially defect-free pattern can be obtained with this approach.

There is provided an optical system, including a light-transmitting substrate having at least two major surfaces parallel to each other edges, and an optical device for coupling light into the substrate by total internal reflection. The device includes a polarization sensitive reflecting surface.

This invention relates to a distributed disturbance sensing device based on polarization sensitive optical frequency domain reflectometry (OFDR) and the related demodulation thereof. The device, adopting OFDR, polarization controlling and analysis techniques, consists of a ultra-narrow linewidth tunable laser source module, polarization generating and polarization splitting balanced detecting module, laser source optical frequency and phase monitoring module, high-speed optical switch and so on to establish a large-scale and long-distance optical sensing network. The demodulation method consists of analysis the polarization information from sensing optical fiber, the method of suppressing and compensating of the non-linear optical frequency and the laser phase noise, super-resolution analyzing, advanced denoising method and the polarization information analysis method based on Jones and Mueller's matrices using distributed wave plate model of optical fiber.

The scanning speed of a sample in Doppler OCT, etc., is increased to enable quick measurement of blood flow rate, blood flow volume, etc. Wideband light from a light source 2 is linearly polarized by a polarization controller 3 and this linearly polarized beam is split into vertically polarized light and horizontally polarized light using a Wollaston prism 14 at a sample arm, which are then irradiated simultaneously onto two different locations of the sample in the scanning direction using a galvanometer mirror18, and reference light from a reference arm 5 and object light from a sample arm 6 are merged and caused to interfere with each other, with the resulting interference signal light passed through a diffraction grating 26 for spectroscopy, while the horizontal component and vertical component are separated by a polarized beam splitter 28, to simultaneously measure the components with two polarization-sensitive optical detectors 29, 30 and thereby obtain two tomography images of the same location at different times by one mechanical scan, thus allowing the amount of temporal change in phase to be measured using the two tomography images.

A method of visually quantifying a test material along with an imaging apparatus for practicing the method is disclosed. The method comprises: (a) illuminating the test material at a known angle of incidence with diffuse light of a known and adjustable polarization state; (b) receiving light from the test material with a polarization state modified by the test material; (c) measuring an intensity of the polarization components of the received light for each illuminated pixel substantially simultaneously; (d) calculating the Stokes Vector in two dimensions for each illuminated pixel; and (e) creating an image map for the known polarization state. The method may also include adjusting the known polarization or the incident angle of the diffuse light to create additional image maps. The method and apparatus are intended for use in medical imaging including minimally invasive surgery.

Generally, and in one form of the present invention, is a polarization-maintaining fiber-based polarization sensitive optical low coherence reflectometer for depth resolved birefringence measurement. With the present invention, linear birefringence of a sample may be measured from data recorded in a single A-Scan. In addition, the present invention provides for the simultaneous measurement of retardation and orientation of birefringent axes, wherein measured retardation is insensitive to sample rotation in the plane perpendicular to ranging.

OCT apparatus includes an interferometer, having an input beam splitter and a 50 / 50 output splitter. The splitting ratio of the input splitter may be optimized depending on the source power of light source and on the mismatch of the balanced receiver. The input splitter is a plate beam-splitter to minimize the stray reflected light in the interferometer and allow sequential operation of the apparatus in the OCT or in the confocal regime. The switching between the two regimes may be at will, or synchronous with the en-face scanning which results in quasi-simultaneous OCT / confocal imaging or in alternatives frames, confocal and OCT. By using polarization sensitive elements, two channels are provided in each regime, OCT and confocal. The two confocal polarization sensitive channels may allow adjustments of compensators prior to OCT measurements or OCT imaging.

Polarization sensitive common path OCT / OCR devices are presented. Optical radiation from a source is converted into two cross-polarized replicas propagating therethrough with a predetermined optical path length difference. The two cross-polarized replicas are then delivered to an associated sample by a delivering device, which is, preferably, an optical fiber probe. A combination optical radiation is produced in at least one secondary interferometer by combining a corresponding portion of an optical radiation returning from the associated sample with a reference optical radiation reflected from a tip of an optical fiber of the optical fiber probe. Subject to a preset optical path length difference of the arms of the at least one secondary interferometer, a cross-polarized component, and / or a parallel-polarized component of the combined optical radiation, are selected. The topology of the devices allows for time domain, as well as for frequency domain registration.

Methods, fourier domain optical coherence tomography (FDOCT) interferometers and computer program products are provided for removing undesired artifacts in FDOCT systems using continuous phase modulation. A variable phase delay is introduced between a reference arm and a sample arm of an FDOCT interferometer using continuous phase modulation. Two or more spectral interferograms having different phase delay integration times are generated. The spectral interferograms are combined using signal processing to remove the undesired artifacts. Systems and methods for switching between stepped and continuous phase shifting Fourier domain optical coherence tomography (FDOCT) and polarization-sensitive optical coherence tomography (PSOCT) are also provided herein.

Arrangements for combination and fast-axis alignment of fast-axes of diode-laser beams are disclosed. Alignment arrangements include providing each diode-laser with a corresponding alignable fast-axis collimating lens, providing individually alignable mirrors for steering an re-orienting beams from each diode-laser, and providing single diode-laser slab-modules in which the diode-laser beams can be pre-aligned to a common propagation-axis direction, and in which edges and surfaces of the slabs can be used to align the fast and slow-axes of the beams. Beam combination methods include combination by dichroic elements, polarization-sensitive elements, and optical fiber bundles.

A compact, non-phased-array, electronically reconfigurable antenna (ERA) system with at least two operational modes has a first operational objective that is polarization-sensitive null steering (PSNS) and a second operational objective that is direction-finding (DF). The system can rapidly switch between two operational states. In the first state, the system behaves like a polarization filter (PF) and operates as a controlled reception pattern antenna (CRPA), while in the second state the system behaves as an angle-of-arrival (AOA) sensor and operates as a fixed reception pattern antenna (FRPA). The system may include a spiral-mode antenna with both feed and load ports; a mode-forming network; an electronics package; and feedback control electronics. Radio frequency (RF) interference rejection and RF direction-finding may be performed as well as reduction and / or elimination of multiple jamming signals that are intentionally or unintentionally directed at a Global Positioning System (GPS). The determination of direction and location of the source of jamming signals may also be achieved.

A fiber laser cavity that includes a laser gain medium for receiving an optical input projection from a laser pump. The fiber laser cavity further includes a positive dispersion fiber segment and a negative dispersion fiber segment for generating a net negative dispersion for balancing a self-phase modulation (SPM) and a dispersion induced pulse broadening / compression in the fiber laser cavity for generating an output laser with a transform-limited pulse shape wherein the laser gain medium further amplifying and compacting a laser pulse. The gain medium further includes a Ytterbium doped fiber for amplifying and compacting a laser pulse. The fiber laser cavity further includes a polarization sensitive isolator and a polarization controller for further shaping the output laser.

There is provided an optical system, including a light-transmitting substrate having at least two major surfaces parallel to each other edges, and an optical device for coupling light into the substrate by total internal reflection. The device includes a polarization sensitive reflecting surface.

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 display system has a controlled transmission mirror disposed between the light sources and the display panel. The controlled transmission mirror includes a light-diverting input coupling element facing the light sources, a light-diverting output coupling element facing the display panel and a multilayer reflector between the input and output coupling elements. The controlled transmission mirror laterally spreads the light, making the illumination of the panel more uniform. The controlled transmission mirror may include a transparent substrate between the input and output coupling elements for additional light spreading. The light sources may be positioned within the controlled transmission mirror, rather than behind it. The output coupling element can be insensitive to polarization, so the light passing out of the controlled transmission mirror is unpolarized, or the output coupling element can be polarization sensitive so that the output light is polarized.

A polarization element and a polarization-sensitive optical isolator are integrated to form an integrated VOA. A preferred embodiment uses a liquid crystal cell as the polarization element to which is attached an optical isolator core of a first polarizer, Faraday rotator, and second polarizer. Voltage on the liquid crystal cell electrodes controls the amount of polarized light from the liquid crystal cell passing through the first polarizer and light in the opposite direction is blocked. The integrated VOA can be mounted within a laser device package so that the power of the source laser diode on the output fiber can be controlled and yet the laser diode is protected from light undesirably entering laser device package through the output fiber.

A fiber laser cavity that includes a laser gain medium for receiving an optical input projection from a laser pump. The fiber laser cavity further includes a positive dispersion fiber segment and a negative dispersion fiber segment for generating a net negative dispersion for balancing a self-phase modulation (SPM) and a dispersion induced pulse broadening / compression in the fiber laser cavity for generating an output laser with a transform-limited pulse shape wherein the wherein said laser gain medium further comprising a double cladding Ytterbium-doped Photonics crystal fiber (DC YDPCF) for amplifying and compacting a laser pulse. The fiber laser cavity further includes a polarization sensitive isolator and a polarization controller for further shaping the output laser.

A polarization-sensitive infrared (IR) detector array for use in infrared cameras and other IR based instruments, is comprised of multiple corrugated quantum well infrared photodetector elements (C-QWIP) that form a unitary detector unit (cell). The array is preferably two-dimensional, which can detect polarization contrast of an observed object in a scene. Each detector unit (cell) is formed by a group of C-QWIP detector elements having different groove orientations and cross sections. Each detector unit (cell) has at least two C-QWIP detector elements with their respective corrugations orthogonally oriented. Infrared detection by these detector cells is primarily by polarization contrast, compared to intensity contrast, which is well known in the art. By measuring polarization of reflected light from the observed object, the type of material can also be identified. A first array embodiment of the invention comprises four C-QWIP elements that form a cell. The second array embodiment of the invention comprises a detector having two C-QWIPs to form a detector cell.

Implementations of augmented reality (AR) / virtual reality (VR) display devices with optical arrangements that are compact and brighter than traditional pancake optics are disclosed herein. One embodiment provides a display device in which the traditional pancake optics' concave 50 / 50 beam splitter mirror element is replaced with a linearly polarization-selective mirror element, producing four times the brightness of traditional pancake optics while being approximately half as thick as a simple magnifier. In another embodiment, a display device includes both the concave linearly polarization-selective mirror element and a circularly polarization-selective mirror element, producing even brighter output. In a further embodiment, a display device includes a flat (rather than concave) linearly polarization-selective mirror element and one or more additional lens elements that collimate light, which may reduce aberrations and / or thickness. In yet another embodiment, the arrangement of optical elements is “flipped” such that the polarization-selective mirror element is flat and relatively easier to manufacturer.

Terahertz metamaterials comprise a periodic array of resonator elements disposed on a dielectric substrate or thin membrane, wherein the resonator elements have a structure that provides a tunable magnetic permeability or a tunable electric permittivity for incident electromagnetic radiation at a frequency greater than about 100 GHz and the periodic array has a lattice constant that is smaller than the wavelength of the incident electromagnetic radiation. Microfabricated metamaterials exhibit lower losses and can be assembled into three-dimensional structures that enable full coupling of incident electromagnetic terahertz radiation in two or three orthogonal directions. Furthermore, polarization sensitive and insensitive metamaterials at terahertz frequencies can enable new devices and applications.

A compact, non-phased-array, electronically reconfigurable antenna (ERA) system with at least two operational modes has a first operational objective that is polarization-sensitive null steering (PSNS) and a second operational objective that is direction-finding (DF). The system can rapidly switch between two operational states. In the first state, the system behaves like a polarization filter (PF) and operates as a controlled reception pattern antenna (CRPA), while in the second state the system behaves as an angle-of-arrival (AOA) sensor and operates as a fixed reception pattern antenna (FRPA). The system may include a spiral-mode antenna with both feed and load ports; a mode-forming network; an electronics package; and feedback control electronics. Radio frequency (RF) interference rejection and RF direction-finding may be performed as well as reduction and / or elimination of multiple jamming signals that are intentionally or unintentionally directed at a Global Positioning System (GPS). The determination of direction and location of the source of jamming signals may also be achieved.