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.

Calibration of spatial light modulators suffering from spatially varying phase response

Abstract: We present a method for converting the desired phase values of a hologram to the correct pixel addressing values of a spatial light modulator (SLM), taking into account detailed spatial variations in the phase response of the SLM. In addition to thickness variations in the liquid crystal layer of the SLM, we also show that these variations in phase response can be caused by a non-uniform electric drive scheme in the SLM or by local heating caused by the incident laser beam. We demonstrate that the use of a global look-up table (LUT), even in combination with a spatially varying scale factor, generally does not yield sufficiently accurate conversion for applications requiring highly controllable output fields, such as holographic optical trapping (HOT). We therefore propose a method where the pixel addressing values are given by a three-dimensional polynomial, with two of the variables being the (x;y)-positions of the pixels, and the third their desired phase values. The coefficients of the polynomial are determined by measuring the phase response in 8×8 sub-sections of the SLM surface; the degree of the polynomial is optimized so that the polynomial expression nearly replicates the measurement in the measurement points, while still showing a good interpolation behavior in between. The polynomial evaluation increases the total computation time for hologram generation by only a few percent. Compared to conventional phase conversion methods, for an SLM with varying phase response, we found that the proposed method increases the control of the trap intensities in HOT, and efficiently prevents the appearance of strong unwanted 0th order diffraction that commonly occurs in SLM systems.

Light source system and related projection system

Abstract: The embodiment of the invention discloses a light source system which comprises a light emitting device, a light splitting system, a first spatial light modulator and a second spatial light modulator. The light emitting device is used for emitting first light and second light in sequence. The light splitting system is used for splitting the first light from the light emitting device into first range wavelength light and second range wavelength light which are emitted along a first light channel and a second light channel respectively and further used for emitting at least some second light from the light emitting device along the first light channel. The first spatial light modulator is used for modulating the light emitted by the light splitting system along the first light channel. The second spatial light modulator is used for modulating at least some light emitted by the light splitting system along the second light channel. The light source system is high in light emitting efficiency and low in cost.

Personal Display Using an Off-Axis Illuminator

Abstract: Certain embodiments include a head mounted display for displaying images that can be viewed by a wearer when the display is worn on the wearer's head. The display can include a spatial light modulator having an array of pixels selectively adjustable for producing spatial patterns. The array of pixels can define a substantially planar reflective surface on the spatial light modulator. The display can further include a light source. The display can also include illumination optics disposed to receive light from the light source and direct light onto the planar reflective surface of the spatial light modulator at an angle with respect to the surface normal of the planar reflective surface. The display can include imaging optics disposed with respect to the spatial light modulator to receive light from the spatial light modulator. The display can also include headgear for supporting the spatial light modulator, imaging optics, and reflector.

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.

Holographic recording using a digital micromirror device

Abstract: We describe the use of a digital micromirror device (Texas Instruments, Inc. ' s DMDTM) as a spatial light modulator forholographic applications. Questions of the interferometric effects of the moving mirror structure and the appropriateness ofpulse-width modulation for grayscale imaging are addressed. Compensation for the particular attributes of DMD imaginghas allowed the creation of full-color holographic stereograms of high image quality.Keywords: holography, spatial light modulator (SLM), digital micromirror device (DMD) 1. INTRODUCTION Spatial light modulators (SLMs) are key components of holographic stereogram printer systems. They are used to display the sequence of two-dimensional stereoscopic perspective views that are being holographically recorded. Because allinformation about the object scene is transduced by the SLM, it is a very important factor in the determination of the finalholographic image quality. Some SLMs typically used for holography include: positive transparency film (35