756 results about "Spatial modulation" patented technology

A combination of a scanning laser ophthalmoscope and external laser sources (52) is used for microphotocoagulation and photodynamic therapy, two examples of selective therapeutic laser. A linkage device incorporating a beamsplitter (56) and collimator-telescope (60) is adjusted to align the pivot point (16) of the scanning lasers (38, 40) and external laser source (52). A similar pivot point minimizes wavefront aberrations, enables precise focusing and registration of the therapeutic laser beam (52) on the retina without the risk of vignetting. One confocal detection pathway of the scanning laser ophthalmoscope images the retina. A second and synchronized detection pathway with a different barrier filter (48) is needed to draw the position and extent of the therapeutic laser spot on the retinal image, as an overlay (64). Advanced spatial modulation increases the selectivity of the therapeutic laser. In microphotocoagulation, an adaptive optics lens (318) is attached to the scanning laser ophthalmoscope, in proximity of the eye. It corrects the higher order optical aberrations of the eye optics, resulting in smaller and better focused applications. In photodynamic therapy, a spatial modulator (420) is placed within the collimator-telescope (60) of the therapeutic laser beam (52), customizing its shape as needed. A similar effect can be obtained by modulating a scanning laser source (38) of appropriate wavelength for photodynamic therapy.

Improved apparatus and methods for spatial light modulation are disclosed which utilize optical cavities having both front and rear reflective surfaces. Light-transmissive regions are formed in the front reflective surface for spatially modulating light.

The selection of the spatial mode together with modulation and encoding schemes based on channel condition measurements requested from MS forms a basis for selecting a best transmission data rate in a wireless link in every channel conditions. A method and network element comprising multiple-input multiple-output (MIMO) capable antenna technology allows the use of a best transmission data rate in the channel if selection of transmission mode has been made correctly. The thresholds for transmission mode selections are pre-determined and compared to instantaneous channel quality information. The practical MIMO solution based on correct selection procedure provides also continuous sufficient channel condition for terminal users when the user moves from LOS situation to NLOS situation.

The objective of the present invention is providing a method for fabricating high quality diffractive waveplates and their arrays that exhibit high diffraction efficiency over large area, the method being capable of inexpensive large volume production. The method uses a polarization converter for converting the polarization of generally non-monochromatic and partially coherent input light beam into a pattern of periodic spatial modulation at the output of said polarization converter. A substrate carrying a photoalignment layer is exposed to said polarization modulation pattern and is coated subsequently with a liquid crystalline material. The high quality diffractive waveplates of the present invention are obtained when the exposure time of said photoalignment layer exceeds by generally an order of magnitude the time period that would be sufficient for producing homogeneous orientation of liquid crystalline materials brought in contact with said photoalignment layer. Compared to holographic techniques, the method is robust with respect to mechanical noises, ambient conditions, and allows inexpensive production via printing while also allowing to double the spatial frequency of optical axis modulation of diffractive waveplates.

A method and apparatus for reading a microbead having a code thereon is provided wherein the code is projected on and read from a Fourier plane. The microbead may be 1-1000 microns (um) or smaller in feature size. The code is projected on the Fourier plane by scattering input light off the microbead. The scattered light from the microbead is directed through an optical arrangement having a transform lens for projecting the code on the Fourier plane, and read on the Fourier plane using a charge coupled device (CCD) or other similar device. The code may include periodic layers of material having different refractivities or phase, including index of refraction differences; periodic spatial modulations having a different phase or amplitude; a periodic binary phase change used to code information in the Fourier plane; a photonic crystal used to encode the information on the microbead, wherein a pattern of holes causes interference between incident and scattered light to form spatial and spectral patterns in the far field that are unique to the pattern of holes; or may be formed in the microbead using a single photoactive inner region, a series of longitudinal holes, different fluorescence regions, or concentric rings of material in a preform.

The present invention provides a design framework that is used to develop new types of constrained turbo block convolutional (CTBC) codes that have higher performance than was previously attainable. The design framework is applied to design both random and deterministic constrained interleavers. Vectorizable deterministic constrained interleavers are developed and used to design parallel architectures for real time SISO decoding of CTBC codes. A new signal mapping technique called constrained interleaved coded modulation (CICM) is also developed. CICM is then used to develop rate matching, spatial modulation, and MIMO modulation subsystems to be used with CTBC codes and other types of codes. By way of example, embodiments are primarily provided for improved 5G LTE and optical transport network (OTN) communication systems. Detailed descriptions of embodiments are also provided that combine aspects of MIMO and spatial modulation systems to improve bandwidth efficiency. Such embodiments are applicable to multi-antenna and single antenna MIMO systems as well as multichannel systems, OFDM systems, and TDM systems.

Methods, systems, and apparatuses are provided for measuring one or more sinusoidal Fourier components of an object. A structured second radiation is generated by spatially modulating a first radiation. The structured second radiation illuminates the object, The structured second radiation is scaled and oriented relative to the object. The object produces a third radiation in response to the illuminating. A single-element detector detects a portion of the third radiation from multiple locations on the object substantially simultaneously for each spatial modulation of the first radiation and for each orientation of the second radiation. A time-varying signal is produced based on said detected portion of the third radiations. One or more characteristics of the one or more sinusoidal Fourier components of the object are estimated based on the time-varying signal.

Disclosed are apparatus and methods for measuring a characteristic, such as overlay, of a semiconductor target. In general, order-selected imaging and/or illumination is performed while collecting an image from a target using a metrology system. In one implementation, tunable spatial modulation is provided only in the imaging path of the system. In other implementations, tunable spatial modulation is provided in both the illumination and imaging paths of the system. In a specific implementation, tunable spatial modulation is used to image side-by-side gratings with diffraction orders ±n. The side-by-side gratings may be in different layers or the same layer of a semiconductor wafer. The overlay between the structures is typically found by measuring the distance between centers symmetry of the gratings. In this embodiment, only orders ±n for a given choice of n (where n is an integer and not equal to zero) are selected, and the gratings are only imaged with these diffraction orders.

A plasma etch process etches high aspect ratio openings in a dielectric film on a workpiece in a reactor having a ceiling electrode overlying the workpiece and an electrostatic chuck supporting the workpiece. The process includes injecting a polymerizing etch process gas through an annular zone of gas injection orifices in the ceiling electrode, and evacuating gas from the reactor through a pumping annulus surrounding an edge of the workpiece. The high aspect ratio openings are etched in the dielectric film with etch species derived from the etch process gas while depositing a polymer derived from the etch process gas onto the workpiece, by generating a plasma in the reactor by applying VHF source power and/or HF and/or LF bias power to the electrodes at the ceiling and/or the electrostatic chuck. The process further includes slowing the deposition rate of the polymer, minimizing etch stop and/or increasing the etch rate in a region of the workpiece typically the center by injecting oxygen or nitrogen and/or high-fluorine containing gas through gas injection orifice in the corresponding region of the ceiling electrode, and adjusting the flow rate of the oxygen or nitrogen and/or high-fluorine containing gas through the gas injection orifice to minimize the difference between profiles and etch depths at the workpiece center and the workpiece periphery.

The present invention makes it possible to reduce the size of an optical system for multiplex recording or reproduction of information utilizing holography.

A pick-up (11) of an optical information recording/reproducing apparatus generates information light by spatially modulating laser light emitted by a light source device (25) with a spatial light modulator (18) depending on the information to be recorded and generates reference light for recording having a spatially modulated phase by spatially modulating the phase of laser beam emitted by the light source device (25) with a phase-spatial light modulator (17). The information light and the reference light for recording are projected upon an optical information recording medium (1) such that they converge in different positions, and information is recorded in the hologram layer (3) in the form of an interference pattern as a result of interference between the information light reflected by a reflecting film (5) and the reference light for recording. The positioning of the information light and the reference light for recording is carried out based on information recorded in address servo areas (6).

Frequency filtering of spatially modulated or “tagged” MRI data in the spatial frequency k-space domain with subsequent 2DFT to the spatial domain and pixel-by-pixel arithmetic calculations provide robust ratio values that can be subjected to inverse trigonometric functions to derive B1 maps for an MRI system.

Apparatus and method for recording and reproducing optical information using holography is designed to provide a small configuration and to improve the S/N ratio of reproduced information. During recording, a phase spatial light modulator generates information light spatially modulated in phase based on information to be recorded, and recording-specific reference light, that irradiate an information recording layer of an optical recording medium to record the information in the form of an interference pattern, resulting from interference between the information light and the recording-specific reference light. During reproduction, reproduction-specific reference light irradiates the information recording layer to generate reproduction light which is superimposed on the reproduction-specific reference light to generate composite light. The composite light is detected by a photodetector to reproduce the information.

A novel radiation detector, a detection principle and an associated structure are provided for semiconductor substrate detectors in general and for CMOS based circuits in particular. For an optical detector, photons absorbed in the neutral zone of the substrate generate electron hole pairs that migrate by diffusion. A shadow mask gives a spatial modulation to the incident, and consequently, to the absorbed light in the semiconductor substrate. By measuring the magnitude of the spatial frequency component in the minority carrier distribution with a spatial frequency corresponding to that of the shadow mask, a fast detector is conceived. A shadow mask with higher spatial modulation frequency delivers a faster turn-off. The combination of a plurality of these detectors with an image fiber forms a basic system for constructing high-speed parallel optical interconnects between chips.

Laser lines at 635 nm or longer (ideally 647 nm) are preferred for red, giving energy-efficient, bright, rapid-motion images with rich, full film-comparable colors. Green and blue lines are used too—and cyan retained for best color mixing, an extra light-power boost, and aid in speckle suppression. Speckle is suppressed through beam-path displacement—by deflecting the beam during projection, thereby avoiding both absorption and diffusion of the beam while preserving pseudocollimation (noncrossing rays). The latter in turn is important to infinite sharpness. Path displacement is achieved by scanning the beam on the liquid-crystal valves (LCLVs), which also provides several enhancements—in energy efficiency, brightness, contrast, beam uniformity (by suppressing both laser-mode ripple and artifacts), and convenient beam-turning to transfer the beam between apparatus tiers. Preferably deflection is performed by a mirror mounted on a galvanometer or motor for rotary oscillation; images are written incrementally on successive portions of the LCLV control stage (either optical or electronic) while the laser “reading beam” is synchronized on the output stage. The beam is shaped, with very little energy loss to masking, into a shallow cross-section which is shifted on the viewing screen as well as the LCLVs. Beam-splitter/analyzer cubes are preferred over polarizing sheets. Spatial modulation provided by an LCLV and maintained by pseudocollimation enables imaging on irregular projection media with portions at distinctly differing distances from the projector—including domes, sculptures, monuments, buildings; waterfalls, sprays, fog, clouds, ice; scrims and other stage structures; trees and other foliage; land and rock surfaces; and even assemblages of living creatures including people.

The invention relates to a laser system for the ionization of a sample by matrix-assisted laser desorption in mass spectrometric analysis. The invention consists in providing an adjustable laser system which, in one setting, generates a single intensity peak on the sample and, in another setting, a multiplicity of intensity peaks, with the half-width, intensity, spatial arrangement and/or degree of spatial modulation of the single intensity peak and/or the intensity peaks being adjustable.