Showing papers on "Spatial light modulator published in 2002"

Spatial light modulators with light blocking/absorbing areas

Abstract: A projection system, a spatial light modulator, and a method for forming a micromirror array such as for a projection display are disclosed. The spatial light modulator can have two substrates bonded together with one of the substrates comprising a micro-mirror array. The two substrates can be bonded at the wafer level after depositing a getter material and/or solid or liquid lubricant on one or both of the wafers if desired. In one embodiment of the invention, one of the substrates is a light transmissive substrate and a light absorbing layer is provided on the light transmissive substrate to selectively block light from passing through the substrate. The light absorbing layer can form a pattern, such as a frame around an array of micro-mirrors.

Optics arrangements including light source arrangements for an active matrix liquid crystal image generator

Abstract: A system for producing modulated light is disclosed. The system comprises a spatial light modulator including a light modulating medium switchable between different states so as to act on light in ways which form overall patterns of modulated light. The system also includes an arrangement for switching the modulating medium between the different states in a controlled way and an illumination arrangement for producing a source of light. The system further includes an optics arrangement for directing light from the source of light into the spatial light modulator and for directing light from the spatial light modulator through a predetermined source imaging area. The optics arrangement cooperates with the illumination arrangement and the spatial light modulator so as to produce a real image of the source of light within the source imaging area such that an individual is able to view a virtual image of the overall patterns of modulated light from the source imaging area. A variety of novel optics arrangements are disclosed including specific combinations of different light sources, diffusing plates, polarizers, beam splitters, analyzers, lenses, mirrors, and holographic optical elements which allow the overall optical arrangement to be miniaturized to the same degree and in coordination with the spatial light modulator. The different light sources include using a plurality of light sources, such as LEDs, to form an array of light sources, each of the light sources providing light to a corresponding portion of the spatial light modulator.

Real-time three-dimensional object reconstruction by use of a phase-encoded digital hologram.

Abstract: A three-dimensional (3D) object reconstruction technique that uses only phase information of a phase-shifting digital hologram and a phase-only spatial-light modulator is proposed. It is well known that a digital hologram can store both amplitude and phase information of an optical electric field and can reconstruct the original 3D object in a computer. We demonstrate that it is possible to reconstruct optically 3D objects using only phase information of the optical field calculated from phase-shifting digital holograms. The use of phase-only information enables us to reduce the amount of data in the digital hologram and reconstruct optically the 3D objects using a liquid-crystal spatial light modulator without optical power loss. Numerical evaluation of the reconstructed 3D object is presented.

Spatial light modulators with light absorbing areas

Abstract: A projection system, a spatial light modulator, and a method for forming micromirrors are disclosed. A substrate comprises circuitry and electrodes for electrostatically deflecting micromirror elements that are disposed within an array of such elements forming the spatial light modulator. In one embodiment, the substrate is a silicon substrate having circuitry and electrodes thereon for electrostatically actuating adjacent micromirror elements, and the substrate is fully or selectively covered with a light absorbing material.

MEMS-actuated color light modulator and methods

Abstract: A light modulator has one or more gratings and one or more MEMS actuators operable to move the gratings for selectively modulating light from an input light source. Certain embodiments have a plurality of blazed gratings arranged parallel to a plane and movable linearly parallel to the plane by MEMS actuators. Each of the gratings is individually blazed for light of a selected color such as red, green or blue. Associated with the gratings may be portions providing black and/or white outputs. An aperture spaced apart from the plane allows color(s) selected from an input white-light source to be directed to an output. An array of MEMS-actuated modulation devices provides a color spatial light modulator. Other embodiments have a grating adapted to be tilted by a MEMS actuator, either continuously through a range of angles or to a selected angle of a set of predetermined discrete angles, to direct selected wavelengths diffracted by the grating toward collection optics for a modulated light output. Methods specially adapted for making and using such light modulators are disclosed.

Image projecting device and method

Abstract: An image projecting device and method are presented. The device comprises a light source system operable to produce a light beam to impinge onto an active surface of a spatial light modulator (SLM) unit formed by an SLM pixel arrangement; and a magnification optics accommodated at the output side of the SLM unit. The light beam impinging onto the SLM pixel arrangement has a predetermined cross section corresponding to the size of said active surface. The SLM unit comprises first and second lens' arrays at opposite sides of the pixel arrangement, such that each lens in the first array and a respective opposite lens in the second array are associated with a corresponding one of the SLM pixels

Fully dynamic multiple-beam optical tweezers

Abstract: We demonstrate a technique for obtaining fully dynamic multiple-beam optical tweezers using the generalized phase contrast (GPC) method and a phase-only spatial light modulator (SLM). The GPC method facilitates the direct transformation of an input phase pattern to an array of high-intensity beams, which can function as efficient multiple optical traps. This straightforward process enables an adjustable number of traps and realtime control of the position, size, shape and intensity of each individual tweezer-beam in arbitrary arrays by encoding the appropriate phase pattern on the SLM. Experimental results show trapping and dynamic manipulation of multiple micro-spheres in a liquid solution.

Defective pixel compensation method

Abstract: The present invention relates to a method for compensating the impact of at least one defective pixel with a known position in a spatial light modulator (SLM) when creating a pattern of the SLM on a work piece covered with a layer sensitive to electromagnetic radiation. A source for emitting electromagnetic radiation is provided. Said radiation is illuminating said SLM having a plurality of modulating elements (pixels). In a writing pass an image of said modulator is projected on said work piece. A compensation for defective pixels in at least one other writing pass is performed. The invention also relates to an apparatus for performing said method.

Interactive light-driven and parallel manipulation of inhomogeneous particles

Abstract: A light-driven micromanipulation system with real-time userfeedback control is used to simultaneously trap colloidal suspensions enabling a unique interactive sorting capability and arbitrary patterning of microscopic particles The technique is based on a straightforward phase-tointensity conversion generating multiple beam patterns for manipulation of particles in the observation plane of a microscope Encoding of phase patterns in a spatial light modulator, which is directly controlled by a computer, allows for dynamic reconfiguration of the trapping patterns, where independent control of the position, size, shape and intensity of each beam is possible Efficient sorting of microsphere mixtures of distinct sizes and colors using multiple optical traps is demonstrated

A radiation conditioning system

Abstract: A holographic imaging system and method includes a radiation source for generating radiation. A data base has a set of elements, each element is indicative of a trajectory of a light ray exiting a point in a recorded scene. A spatial light modulator is receptive of the radiation from the radiation source and the elements of the data base mapped to the spatial light modulator, thereby projecting from the spatial light modulator an optical signal in the nature of a two dimensional bitmap of the recorded scene. A diffractive optical element includes a set of basis fringes receptive of the projected optical signal from the spatial light modulator for diffracting the optical signal in a specified direction. A multiplexer is receptive of the elements of the data base for multiplexing the elements of the data base to the spatial light modulator. A timing device synchronizes multiplexing the elements of the data base to the spatial light modulator and diffracting the optical signal in a specified direction.

Multidimensional control of femtosecond pulses by use of a programmable liquid-crystal matrix

Abstract: We report the automated generation of high-fidelity spatiotemporally shaped femtosecond pulses by use of an optically addressed, two-dimensional liquid-crystal spatial light modulator. A single input pulse was divided into many independent regions, and each region was shaped temporally. By changing the imaging geometry we accomplished either real-space or wave-vector shaping.

Apparatus for projecting a line of light from a diode-laser array

Abstract: An illumination system for projecting a line of light includes a linear array of diode lasers having a fast and a slow axis and an optical system aligned with the linear array and having different optical power in the fast and slow axes. The optical system is arranged to focus fast-axis diverging rays from the array in a fast axis focal plane of the optical system, and arranged to form slow axis diverging rays of the array into a plurality of bundles of parallel rays, one for each diode-laser, in the array. The bundles of parallel rays intersect in the fast-axis focal plane, such that light from the diode-lasers is formed into a line of light in the fast-axis focal plane. The line of light has a width in the fast axis and a length in the slow axis. The illuminator is useful as an illuminator for a linear spatial light modulator array.

Projection display with multiply filtered light

Abstract: A projection system is disclosed that has a light source of multiple wavelengths, a spatial light modulator and projection optics for projecting an image to be viewed by a viewer or to be displayed on a target. Also provided are one or more color sequencing devices which filter the light multiple times. Whether a single or plural color sequencing elements are provided, a single light beam passes at least twice through a sequence of light filters. In one embodiment, two color wheels provide the ability to filter the light multiple times. By changing the physical position or phase of one series of filters relative to another, the brightness and color saturation of the image projected through the projection optics can be changed. The changes in brightness and color saturation can be performed manually by mechanically changing the phase (or position) of the color sequencing device(s) relative to the light beam. Such changes can be performed step-wise of gradually through a continuum of brightness vs. color saturation points.

A dual path programmable array microscope (PAM): simultaneous acquisition of conjugate and non-conjugate images.

Abstract: A programmable array microscope (PAM) incorporates a spatial light modulator (SLM) placed in the primary image plane of a widefield microscope, where it is used to define patterns of illumination and/or detection. We describe the characteristics of a special type of PAM collecting two images simultaneously. The conjugate image (Ic) is formed by light originating from the object plane and returning along the optical path of the illumination light. The non-conjugate image (Inc) receives light from only those regions of the SLM that are not used for illuminating the sample. The dual-signal PAM provides much more time-efficient excitation than the confocal laser scanning microscope (CLSM) and greater utilization of the available emission light. It has superior noise characteristics in comparison to single-sided instruments. The axial responses of the system under a variety of conditions were measured and the behaviour of the novel Inc image characterized. As in systems in which only Ic images are collected (Nipkow-disc microscopes, and previously characterized PAMs), the axial response to thin fluorescent films showed a sharpening of the axial response as the unit cell of the repetitive patterns decreased in size. The dual-signal PAM can be adapted to a wide range of data analysis and collection strategies. We investigated systematically the effects of patterns and unit cell dimensions on the axial response. Sufficiently sparse patterns lead to an Ic image formed by the superposition of the many parallel beams, each of which is equivalent to the single scanning spot of a CLSM. The sectioning capabilities of the system, as given by its axial responses, were similar for a given scan pattern and for processed pseudorandom sequence (PRS) scans with the same size of the unit cell. For the PRS scans, optical sectioning was achieved by a subtraction of an Inc image or, alternatively, a scaled widefield image from the Ic image. Based on the comparative noise levels of the two methods, the non-conjugate subtraction was significantly superior. A point spread function for Ic and Inc was simulated and properties of the optical transfer functions (OTFs) were compared. Simulations of the OTF in non-conjugate imaging did not suffer from the missing cone problem, enabling a high quality deconvolution of the non-conjugate side alone. We also investigated the properties of images obtained by subjecting the Ic and Inc data to a combined maximum likelihood deconvolution.

Apparatus and methods relating to wavelength conditioning of illumination

Abstract: Lighting systems comprising a spectrum former upstream from a reflective pixelated spatial light modulator (reflective SLM), the SLM reflecting substantially all of the light in the spectrum into at least two different light paths, that do not reflect back to the light source or the spectrum former. At least one of the light paths acts as a projection light path and transmits desired light out of the lighting system. The lighting systems provide virtually any desired color(s) and intensity(s) of light, and avoid overheating problems by deflecting unwanted light and other electromagnetic radiation out of the system or to a heat management system. The systems can be part of another system, a luminaire, or any other suitable light source. The systems can provide virtually any desired light, from the light seen at the break of morning to specialized light for treating cancer or psoriasis, and may change color and intensity at speeds that are perceptually instantaneous.

Projection display using a wire grid polarization beamsplitter with compensator

Abstract: A display apparatus ( 10 ) including a light source ( 15 ) for forming a beam of light ( 130 ). A pre-polarizer ( 45 ) polarizes the beam of light ( 130 ) to provide a polarized beam of light. A wire grid polarization beamsplitter ( 50 ) receives the polarized beam of light and transmits the polarized beam of light which has a first polarization, and reflects the polarized beam of light which has a second polarization. A reflective spatial light modulator ( 55 ) selectively modulates the polarized beam of light that has a first polarization to encode image data thereon in order to form a modulated beam ( 360 ) and reflects the modulated beam back to the wire grid polarization beamsplitter ( 50 ). A compensator ( 260 ) is located between the wire grid polarization beamsplitter ( 50 ) and the reflective spatial light modulator ( 55 ) for conditioning oblique and skew rays of the modulated beam ( 360 ). The wire grid polarization beamsplitter ( 50 ) reflects the compensated modulated beam ( 360 ) and the wire gird polarization beamsplitter ( 50 ) is rotated in plane to optimize the contrast. A polarization analyzer ( 60 ) removes residual light of the opposite polarization state from the compensated modulated beam ( 360 ). Image-forming optics ( 20 ) form an image from the compensated modulated beam ( 360 ).

An illumination system for one-dimensional spatial light modulators employing multiple light sources

Abstract: The present invention is directed to illuminating a one-dimensional spatial light modulator (70) using an illumination system employing multiple light sources (10). The illumination system comprises a parallel array of light sources which provides a plurality of light outputs to an optical train (200). The optical train effectively combines the light sources into a single light source. The single light source provides a single light output for uniformly illuminating the spatial light modulator. The optical train includes a first optical train for receiving the light outputs from each light source, magnifying each light output, and overlaying each of the light outputs to form a single real magnified image. A mode conversion lens receives the single real magnified image, converts a mode profile of the single real magnified image into a top hat mode profile, and outputs a diverging light beam with a top hat mode profile. A second optical train shapes the light beam into an appropriate spatial geometry in such a manner that the light beam effectively illuminates the entire spatial light modulator, and directs the light beam onto the spatial modulator.

Advances in liquid crystal spatial light modulators

Abstract: Recent advances in our high-speed analog liquid crystal spatial light modulators (SLMs) will be presented. These advancements include higher pixel density, smaller pixel pitch, greatly improved optical efficiency, and higher speed operation. The new VLSI SLMs can utilize ferroelectric liquid crystal (FLC) or nematic liquid crystal (NLC) to achieve phase-only, amplitude-only and phase-amplitude-coupled modulation. These devices have applications in optical processing, optical storage, holographic display and beamsteering. Design criteria and experimental data will be presented.

Micro-positioning movement of holographic data storage system components

Abstract: According to one aspect, a holographic storage system including micro-actuators is presented. In one example of one aspect of the invention, the device includes a spatial light modulator, a detector, a storage medium, and at least one micro-actuator configured to move at least one of the spatial light modulator, the detector, and the storage medium. The micro-actuators may include a servomechanism or the like to control the positioning of a component based on feedback associated with a misalignment of a detected image. According to another aspect of the invention, various methods for determining component misalignments of a holographic storage system are presented.

Apparatus and method for recording optical information, apparatus and method for reproducing optical information, apparatus for recording/reproducing optical information, and optical information recording medium

Abstract: 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 ).

Maskless conformable lithography

Abstract: Maskless patterning of high-resolution microelectronics features onto large curved substrates. A computer controls individual pixel elements in a spatial light modulator array (SLM) which provides the pattern. Maintaining optical track length constant is by software control of SLM vertical positioning, surface configuration and tilt. SLMs are on/off devices, either reflective or transmissive, such as digital micromirror devices (DMD) and liquid crystal light modulator arrays (LCLM). High-resolution spatial light modulator arrays currently have no capacity for changing or control of their average surface configurations. It is proposed to segment the SLM into smaller array chips, each mounted on a vertical positioner, such as a piezo-actuator, to provide the desired configuration to the surface defined by the spatial light modulator arrays. As an additional means to accommodate the variable surface configuration of the curved surface, a flexmirror (adaptive mirror) may be inserted between projection lens subsystem and the SLM array, defining the wavefront of pixel sub-beams striking the surface of the substrate and enabling the optical conjugates to be kept constant for a greater range of substrate curvatures.

Spatial light modulators with light blocking and absorbing areas

Abstract: A projection system, a spatial light modulator, and a method for forming a MEMS device are disclosed. The spatial light modulator can have two substrates bonded together with one of the substrates comprising a micro-mirror array. The two substrates can be bonded at the wafer level after depositing a getter material and/or solid or liquid lubricant on one or both of the wafers if desired. In one embodiment of the invention, one of the substrates is a light transmissive substrate and a light blocking layer that is preferably a light absorbing layer is provided on the light transmissive substrate to selectively block light from passing through the substrate. The light blocking layer can be formed as a pattern, such as a grid or strips for blocking light from entering gaps between adjacent micro-mirrors.

Automated two-dimensional femtosecond pulse shaping

Abstract: We report the automated generation of high-fidelity spatiotemporally shaped femtosecond pulses using an optically addressed, reflection-mode two-dimensional spatial light modulator. The spatial light modulator has been fully characterized. We performed spatiotemporal pulse shaping by dividing a vertically expanded input pulse into many horizontal regions, each of which was independently shaped through phase-only spectral filtering. The configuration of the imaging optics determined whether real space or wave-vector shaping was performed. We performed cross correlations of shaped waveforms by using a pulse shaper to generate variably delayed pulses, demonstrating time-resolved measurement without beam splitters or delay lines.

Spatial light modulator apparatus

Abstract: A spatial light modulator apparatus for an optical microscope system including an optical head with a mounting flange for mounting the optical head to a port of the microscope, a DMD for generating a pattern image of light, a light source mount for receiving a source of illumination, and one or more optical elements for directing light from the source of illumination to the DMD and to direct the pattern image generated by the DMD to the microscope. A DMD controller has a digital input and is connected to the DMD for driving the individual micromirrors of the DMD to generate the pattern image. A pattern generation subsystem is configured to output pattern image data and a digital interface is connected between the digital input of the DMD controller and the pattern generation subsystem, the digital interface configured to provide a digital drive signal to the DMD controller corresponding to the pattern image data.

Liquid-crystal adaptive optics based on feedback interferometry for high-resolution retinal imaging

Abstract: A novel, to our knowledge, adaptive optical imaging system for high-resolution retinal imaging is described. The system is based on a feedback interferometer, in which two-dimensional output fringe intensity from a Mach-Zehnder interferometer with large radial shear is fed back, with the help of a video projector connected with a CCD camera, to an optically addressed phase-only liquid-crystal spatial light modulator. Experiments to verify the system performance have been conducted by use of an artificial eye consisting of a lens, an aberration plate, and a resolution test target. We observed that an image of the test target (mimicking a retina) blurred by the aberration plate (mimicking ocular aberrations) was successfully restored immediately after our adaptive optics system was activated.

Synthesis of longitudinal coherence functions by spatial modulation of an extended light source: a new interpretation and experimental verifications.

Abstract: Giving a new physical interpretation to the principle of longitudinal coherence control, we propose an improved method for synthesizing a spatial coherence function along the longitudinal axis of light propagation. By controlling the irradiance of an extended quasi-monochromatic spatially incoherent source with a spatial light modulator, we generated a special optical field that exhibits high coherence selectively for a specific pair of points at specified locations along the axis of beam propagation. This function of longitudinal coherence control provides new possibilities for dispersion-free measurements in optical tomography and profilometry. A quantitative experimental proof of principle is presented.

Adaptive beam steering implemented in a ferroelectric liquid-crystal spatial-light-modulator free-space, fiber-optic switch.

Abstract: Active alignment of a 1 x 8 free-space optical switch was studied experimentally. Optical signals, carried on single-mode fibers, were switched by a ferroelectric liquid-crystal-on-silicon spatial light modulator. Continuous measurement of the in-coupled power to the fibers provided feedback for the switch control. The switch automatically located and locked to the output fibers. An advantage with adaptive switches of a similar kind is relaxed geometrical tolerances in the switch assembly. Further, such switches can adapt to possible geometrical changes and light wavelength drift during operation.

Magnetooptic Spatial Light Modulator for Volumetric Digital Recording System

Abstract: A novel reflective magnetooptic spatial light modulator has been fabricated and its dynamic switching testing was investigated. Improvements by a factor of three in pixel switching sensitivity and power consumption could be achieved by the use of a wedge-shaped drive line, compared to the use of a conventional reflective magnetooptic spatial light modulator. Simpler fabrication processes by a factor of two could also be achieved by the use of a drive line which covers most of the surface of the pixel, a non-rectangular channel and a unpatterned insulator layer.

Pulse width modulated spatial light modulators with offset pulses

Abstract: In some embodiments, a display system includes a spatial light modulator including at least one pixel, a pixel source including pixel data corresponding to the pixel, a memory circuit connected to the pixel source and configured to store a pixel value corresponding to the pixel data, a pulse width modulation circuit connected between the memory circuit and the spatial light modulator, the pulse width modulation circuit adapted to generate a pulse to drive the pixel of the spatial light modulator, wherein a duration of the pulse corresponds to the pixel value and wherein the pulse is offset with respect to a start time and an end time of a refresh cycle of the spatial light modulator, and a control circuit connected to at least one of the memory circuit, the spatial light modulator, and the pulse width modulation circuit. Other embodiments are described and claimed.

Programmable multiwavelength modelocked laser

Abstract: A programmable multiwavelength modelocked laser system. Embodiments of the system can use a computer, gratings, optical spectrum analyzer and SLM(spatial light modulator) inside of a laser cavity to control output amplitudes and phase of each of the wavelength channels of a multiple wavelength laser system. The programmable control allows for wavelength intensity(amplitude) levels of up to approximately 16 channels to be controlled and evened out. An InGaAsP SOA based modelocked multiwavelength ring laser is stabilized using a programmable liquid crystal spatial light modulator in a feedback control loop. The system produces 16 independent modelocked RZ wavelength channels at 10 GHz with 0.44 dB flatness and 25 psec pulses.