A tunable liquid crystal (LC) device includes an LC layer between a pair of reflectors forming an optical cavity. The reflectors include conductive layers for applying an electrical signal to the LC layer. One of the conductive layers may include an array of conductive pixels for spatially selective control of the effective refractive index of the LC layer. The phase delay introduced by the LC layer may be greatly increased or magnified by placing the LC layer into the optical cavity. This enables a substantial reduction of the LC layer thickness, which in its turn enables very tight pitches of the LC pixels, with a reduced inter-pixel crosstalk caused by fringing electric fields, as well as faster switching times. A tight-pitch, fast LC device may be used as a configurable hologram or a spatial light modulator.

A holographic display panel comprises a plurality of display units, each display unit comprises at least two adjacent pixels, each pixel comprises: a plurality of sub-pixels; and a plurality of phase plates. Diffractive angles of light coming out of the phase plates corresponding to the sub-pixels in a same pixel are the same, a diffractive angle of first light coming out of the phase plates corresponding to a first pixel in one of the display units is different from a diffractive angle of second light coming out of the phase plates corresponding to a second pixel that is different from the first pixel but in the same display unit, and a reverse extension line of the first light and a reverse extension line of the second light intersect at an image plane position.

A printing device (106) includes a laser source and a LCOS-SLM (Liquid Crystal on Silicon Spatial Light Modulator). The printing device generates a laser control signal and a LCOS-SLM control signal. The laser source (110) generates a plurality of incident laser beams based on the laser control signal. The LCOS-SLM (112) receives the plurality of incident laser beams, modulates the plurality of incident laser beams based on the LCOS-SL M control signal to generate a plurality of holographic wavefronts (214,216) from the modulated plurality of incident laser beams. Each holographic wavefront forms at least one corresponding focal point. The printing device cures a surface layer or sub-surface layer (406) of a target material (206) at interference points of focal points of the plurality of holographic wavefronts. The cured surface layer of the target material forms a three-dimensional printed content.

There is provided a holographic projector comprising a reflective liquid crystal display device. The reflective liquid crystal display device comprises a light-modulating layer between a first substrate and a second substrate substantially parallel to the first substrate. The light-modulating layer comprises planar-aligned nematic liquid crystals having positive dielectric anisotropy. The first substrate is substantially transparent and comprises a first alignment layer arranged to impart a first pre-tilt angle θ.sub.l on liquid crystals proximate the first substrate, wherein θ.sub.1>5°. The second substrate is substantially reflective and comprises a second alignment layer arranged to impart a second pre-tilt angle Θ.sub.2 on liquid crystals proximate the second substrate, wherein θ.sub.2>5°. The reflective liquid crystal display device further comprises a plurality of pixels defined on the light-modulating layer having a pixel repeat distance x, wherein x≤10 μm. The distance d between inside faces of the first substrate and second substrate satisfies 0.5 μm≤d≤3 μm, and the birefringence of the liquid crystal Δη≥0.20. The holographic projector further comprises a display driver arranged to drive the reflective liquid crystal display device to display a hologram by independently-driving each pixel at a respective modulation level selected from a plurality of modulation levels having a phase modulation value.

Apparatus for generating an optical pattern from image points in an image plane, including: a control unit; a micro-mirror array; an illumination unit controllable by the control unit; a focusing unit; the control unit being configured to control one or several micro-mirror groups formed of several micro-mirrors of the multitude of micro-mirrors such that the centroid beams reflected at the micro-mirrors of one of the micro-mirror groups meet in the image plane, and such that optical path lengths of the centroid beams reflected at the micro-mirrors of the respective micro-mirror group are equal from the illumination unit up to the image plane or differ by an integer multiple of a wavelength of the light beams in order to generate an image point of the image points in such a way.

There is provided a head-up display for a vehicle having a window. The head-up display comprises a picture generating unit (410) and an optical system (420). The picture generating unit is arranged to output pictures. The optical system is arranged to receive the pictures output by the picture generating unit and project the pictures onto the window (430) of the vehicle to form a virtual image (450, 707) of each picture within a virtual image area (605). The picture generating unit is arranged to output pictures within a cropped picture area such that the virtual image area (605) has a corresponding cropped shape. FIG. 7 illustrates a perspective view of a three lanes road (501,502,503) onto which a virtual image (707) within a cropped virtual image area (605) is overlaid.

A holographic optical apparatus includes a beam splitting component, a transmission assembly, a focal length modulation component and an optical element. The beam splitting component splits received light into reference light and signal light that are coherent light, and outputs the reference light and the signal light. The focal length modulation component includes a plurality of local length modulation regions with different focal lengths. The optical element includes a recording medium layer with a plurality of recording regions, and each recording region is located in a light-exit path of a focal length modulation region. The transmission assembly is disposed in a light-exit path of the beam splitting component, transmit the reference light to the plurality of recording regions and transmit the signal light to the plurality of focal length modulation regions.

A holographic display apparatus capable of providing an expanded viewing window and a display method are provided. The holographic display apparatus includes an image processor configured to provide computer generated hologram (CGH) data to a spatial light modulator, wherein the image processor is further configured to generate a hologram data array comprising information of the holographic image to be reproduced at the first resolution or a resolution less than the first resolution, perform an off-axis phase computation on the hologram data array at the second resolution, and then, generate the CHG data at the first resolution.

A holographic display system includes a light source that emits coherent light; a lateral displacement beam splitter that optically receives the coherent light and generates first reference light and second reference light; a first spatial light modulator (SLM) and a second SLM that optically receive the first reference light and the second reference light respectively, and construct first phase-only function (POF) light and second POF light respectively; a first beam splitter and a second beam splitter that optically receive the first POF light and the second POF light respectively, and generate first split light and second split light respectively; and a plurality of polarizers disposed between the first SLM and the first beam splitter, and between the second SLM and the second beam splitter, respectively.

A modular routing node includes a single input port and a plurality of output ports. The modular routing node is arranged to produce a plurality of different deflections and uses small adjustments to compensate for wavelength differences and alignment tolerances in an optical system. An optical device is arranged to receive a multiplex of many optical signals at different wavelengths, to separate the optical signals into at least two groups, and to process at least one of the groups adaptively.