Spatial light modulator

About: Spatial light modulator is a research topic. Over the lifetime, 9043 publications have been published within this topic receiving 130143 citations.

Active digital hologram display

Abstract: Certain types of holographic recording materials can be used to updateably record holographic stereograms formed when fringe patterns are generated through interference of an object laser beam containing image information with a reference laser beam. In this manner, calculation of fringe patterns is avoided, and instead perspective information is computed for a scene or object to be displayed, the information is downloaded to display hardware such as a spatial light modulator, and fringe patterns are subsequently generated through interference of an object laser beam containing this information with a reference laser beam in the classic hologram recording scheme. Previously recorded holographic stereograms or component hogels are updated by erasing the stereograms or component hogels and recording updated stereograms or component hogels, or by recording updated stereograms or component hogels in a separate portion of the holographic recording material.

Optical reconstruction of digital holograms recorded at 10.6 μm: route for 3D imaging at long infrared wavelengths

Abstract: We demonstrate the optical reconstruction in the visible range (0.532μm) of digital holograms recorded at long IR wavelengths (10.6μm) by means of a spatial light modulator. By using an integrated recording-reconstruction system, it is, in fact, feasible to achieve direct imaging of holograms acquired outside the visible range, i.e., in the IR spectrum. By choosing a Fourier recording configuration, the reconstructed image, obtained at about a 20 times shorter wavelength than the acquisition image, exhibits minor aberrations, which do not significantly affect the optical reconstruction. The high NA achievable at a long IR wavelength allows us to image large objects at reasonable distances.

Device and method for creating a three dimensional object using mask illumination

Abstract: The apparatus includes a computer, an integrated circuit and software. It has the capability for selective control and adjustment of energy introduction, via a set grayscale value or color value, into a voxel- (volume element) matrix. The imaging unit is controlled such that at least some of the pixels used, are allocated more than two energy steps, for variable energy introduction into the voxel matrix. These energy steps include ON and OFF, a set number of grayscale steps, or a set number of color values. The apparatus is equipped to carry out this process with a grayscale or color mask (i.e. step filters) compensating for the effect of ambient lighting over the entire imaging surface of the construction plane. This forms an overlay for the bitmap used to cause solidification, and promotes uniform energy distribution over the entire projected image. To this end, grayscale values and color values are interpolated between measurement points. The apparatus controls: graphic pixel intersection, area expansion and hardening depth. The apparatus increases the depth of hardening in the Z-direction, in selected regions of the voxel matrix. The apparatus stores grayscale and color values at each pixel in the scanned image bitmap, in memory. This information is alternatively calculated and updated on-line. The imaging unit is included in a projector. It is a spatial light modulator (SLM). The technology of micro-electromechanical systems (MEMS) is employed. Alternatively light emitting diodes (LEDs) are used. An independent claim IS INCLUDED FOR the corresponding method.

Design and fabrication of 10×10 micro-spatial light modulator array for phase and amplitude modulation

Abstract: In this paper, a 10×10 micro-spatial light modulator (micro-SLM) array for phase and amplitude modulation of incident light is designed and fabricated using surface micromachining technology. Hidden spring structure is used in order to maximize the fill-factor and minimize diffraction effect. A designed micro-SLM is composed of a mirror plate, upper electrodes, five support posts, and bottom electrodes. The spring structures are composed of four double crab leg springs for phase modulation (piston mode operation) and two torsional springs for amplitude modulation (tilt mode operation). The micro-SLM is actuated by electrostatic force generated between upper electrode and bottom electrode. In case of phase modulation, the maximum deflection length of mirror plate is designed to be 4 μm and in case of amplitude modulation, micro-SLM is designed to be capable of tilting ±5.4° to reflect incident light. The designed micro-SLM array is successfully fabricated with surface micromachining technology using thick photoresist as a sacrificial layer and aluminum as a structural material. Mirror plate and spring structure are fabricated without initial bending problem. The resulting fill-factor is about 91.7%. Static and dynamic characteristics of the fabricated micro-SLM in the case of amplitude modulation are measured with optical measurement system. In the fields of adaptive optics and pattern recognition system, SLM is used to modulate the phase and amplitude of incident light in order to correct aberration in an optical system through active control of mirror array.

Wish: wavefront imaging sensor with high resolution

Abstract: A system for a wavefront imaging sensor with high resolution (WISH) comprises a spatial light modulator (SLM), a plurality of image sensors and a processor. The system further includes the SLM and a computational post-processing algorithm for recovering an incident wavefront with a high spatial resolution and a fine phase estimation. In addition, the image sensors work both in a visible electromagnetic (EM) spectrum and outside the visible EM spectrum.