An optical device includes a first backlight configured to output first light of a first wavelength through a first output coupler, a first lens disposed to face the first output coupler and having a focal length with respect to the first light, a second backlight including a second output coupler, the second backlight being configured to output second light of a second wavelength through the second output coupler, a second lens disposed to face the second output coupler and having different focal lengths with respect to the first light and the second light, a third backlight including a third output coupler, the third backlight being configured to output third light of a third wavelength through the third output coupler, and a third lens disposed to face the third output coupler and having different focal lengths with respect to the first light, the second light, and the third light.

A display system for presenting a holographic image to a viewer may comprise a coherent light source, a display element, and a computing device operatively connected to the coherent light source and the display element, the coherent light source emitting a light that enters the display element from the same side of the viewer, and the display element comprising a liquid crystal layer and a partially-transmissive-partially-reflective layer, wherein the computing device is configured to provide a control signal to the display element to present the holographic image, wherein the liquid crystal layer receives light from the light source and is controlled by the control signal to modulate a phase of the light from the light source, and wherein the partially-transmissive-partially-reflective layer receives light from the liquid crystal layer and reflects the light back through the liquid crystal layer to the viewer.

A focus modulation optical system and a holographic display device having the focus modulation optical system are disclosed. The holographic display device includes a light source configured to emit a plurality of color lights, a focus modulation optical system including at least one variable focus lens that is configured to change a focusing position of incident light by electrical control of the at least one variable focus lens based on a color of light incident on the variable focus lens, and a spatial light modulator configured to form a holographic image by diffracting light output from the focus modulation optical system.

An illumination device includes a light diffusion device including element diffusion devices that diffuse incident light, a coherent light source that emits coherent light, a shaping optical system that shapes the coherent light, a scanner that adjusts a traveling direction of the coherent light so as to allow the coherent light to scan the light diffusion device, and a light condensing optical system located on a light path of the coherent light from the shaping optical system up to the light diffusion device. The light condensing optical system condenses the coherent light such that a spot area on the light diffusion device is smaller than the element diffusion device. Each element diffusion device diffuses the coherent light incident thereon so as to illuminate an element illumination area corresponding to the element diffusion device.

A hologram for an illumination device for vehicles and a corresponding illumination device are provided. The hologram has a plurality of holographic structures designed for a respectively associated wavelength, wherein the holographic structures have diffraction properties that are identical among one another.

A backlight unit for a binocular-holographic display device and a holographic display device including the same are provided. The backlight unit includes a light source unit which outputs light, a first beam expansion unit which expands, in a first direction, the light output from the light source unit, a second beam expansion unit which expands, in a second direction perpendicular to the first direction, the light output from the first beam expansion unit, and a beam deflection unit which diffracts light incident on the first beam expansion unit. The holographic display device includes the backlight unit, a field lens, and a spatial light modulator.

A holographic display device presents a holographic image within an external part for a vehicle such as a headlight assembly or an exterior rearview mirror assembly. An outer cover defines an interior cavity, with a transparent portion, such as a window, allowing a viewer to see into the interior cavity. A presentation surface inside the interior cavity is illuminated by an image source to display the holographic image, which appears as a 3-dimensional object within the interior cavity, and which appears to be suspended therein. The holographic image may be stationary or moving, and may include a logo, symbol, or other graphic. The image source is may be hidden from direct view. One embodiment includes two circular polarizer to prevent light directly from the image source from being visible, while allowing reflected light to become visible by being having the polarization direction reversed.

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 and methods for 3D-Scanless Holographic Optogenetics with Temporal focusing (3D-SHOT), which allows precise, simultaneous photo-activation of arbitrary sets of neurons anywhere within the addressable volume of the microscope. Soma-targeted (ST) optogenetic tools, ST-ChroME and IRES-ST-eGtACR1, optimized for multiphoton activation and suppression are also provided. The methods use point-cloud holography to place multiple copies of a temporally focused disc matching the dimensions of a designated neuron's cell body. Experiments in cultured cells, brain slices, and in living mice demonstrate single-neuron spatial resolution even when optically targeting randomly distributed groups of neurons in 3D.

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.