A holographic display device includes a light source configured to emit light, the light including first light of a first wavelength, second light of a second wavelength, and third light of a third wavelength; a spatial light modulator configured to form a holographic pattern to modulate the light emitted from the light source and to produce a holographic image; and a focusing optical system configured to focus the holographic image. The focusing optical system includes a fixed-focus optical system having a fixed focal length, and a variable focus optical system having a focal length that is changed by electrical control. The fixed-focus optical system is configured to focus the first light of the first wavelength, the second light of the second wavelength, and the third light of the third wavelength on different positions, respectively, on an optical axis to cancel a chromatic aberration by the variable focus optical system.

A hologram reproducing apparatus is provided that includes a display configured to emit a write beam corresponding to a hologram pattern, a spatial light modulator (SLM) configured to write the hologram pattern according to the write beam and modulate the reproduction beam into a plurality of diffraction beams corresponding to the hologram pattern if a reproduction beam is incident, a light guide plate disposed in a front surface of the SLM, and configured to guide the reproduction beam toward the SLM, a filter configured to filter the plurality of diffraction beams, a lens configured to focus the plurality of diffraction beams filtered through the filter, and a plurality of optical fibers arranged in order to dispose at least one optical fiber to correspond to each of a plurality of pixels included in the display, and configured to transmit the write beam to the SLM.

Methods for selectively stimulating a plurality of light-responsive neurons in a sample are provided. Methods according to certain embodiments include irradiating a sample comprising a plurality of light-responsive neurons with a plurality of holographic images that are each configured to stimulate one or more light-responsive neurons in the sample, wherein the holographic images are created by light projection system that includes a plurality of light sources; a plurality of optical adjustment components; a plurality of spatial light modulators; a controller; a processor; and a computer-readable medium comprising instructions that, when executed by the processor, cause the controller to operate the light sources, optical adjustment components and spatial light modulators to generate and display a plurality of holographic images; direct each of the holographic images to a projection location; and project the holographic images onto the sample at a rate greater than 1 kHz. Light projection systems for irradiating a sample having light-responsive neurons with holographic images are also described.

A holographic projector having an optical path is described. The holographic projector comprises a first spatial light modulator arranged to display a first hologram, and a first light source. The first light source is arranged to illuminate the first spatial light modulator with light of a first wavelength such that a first holographic reconstruction corresponding to the first hologram is formed on a replay plane. The holographic projector further comprises a continuous block of transparent material. At least part of the optical path is formed through the continuous block of transparent material. The transparent material has a refractive index greater than air.

Provided a backlight unit including a light source and a light guide structure configured to guide the light emitted from the light source, the light guide structure includes a first coupler layer including a first output coupler configured to expand light in a first direction and output the expanded light in the first direction to the outside of the light guide structure, and a first expansion coupler configured to expand the light in a second direction perpendicular to the first direction and provide the expanded light in the second direction to the first output coupler, and a second coupler layer including a second output coupler configured to expand light in the first direction and output the expanded light to the outside of the light guide structure, and a second expansion coupler configured to expand light in the second direction and provide the expanded light to the second output coupler.

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-eGtACR 1, 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 backlight device includes: a light source to emit coherent light; an optical path difference generator on the light source, the optical path difference generator including an incident surface and a plurality of light emitting surfaces, the light emitting surfaces being parallel to the incident surface and having different separation distances from the incident surface; a light condenser on the optical path difference generator; a diffuser on the light condenser; and a collimator on the diffuser.

A replicator assembly includes reflective, transmissive, and transparent elements. The reflective element receives and reflects a hologram of a HUD system. The transmissive element includes a partially transmissive portion that receives a reflection of the hologram from the reflective element, outputs N replications of the hologram, and reflects N1 replications of the hologram. The partially transmissive portion is implemented as a continuous transmission neutral density filter across different phase regions. The phase regions of the partially transmissive portion correspond respectively to the N replications. N is an integer greater than or equal to 2. The reflective element reflects the N1 replications of the hologram. The transparent element is disposed between the reflective and transmissive elements and guides the N replications of the hologram between the reflective and transmissive elements. The reflective, transmissive and transparent elements are implemented as a replicator and collectively provide the N replications of the hologram.

Technology is described for methods and systems for a diffractive optic device (525) for holographic projection. The diffractive optic device can include a lens (535) configured to convey a hologram. The lens (535) further comprises a patterned material (510) formed with an array of cells having a non-planar arrangement of cell heights extending from a surface of the patterned material. The lens further optionally comprises a filling material (530) to fill gaps on both surfaces of the patterned material.

An imaging module, including a lens and a transmissive display panel disposed adjacent to each other, and a controller electrically connected to the transmissive display panel, the controller loading a white image on a preset area of the transmissive display panel so that a light beam passes through the preset area. A light beam gating control method, a testing apparatus and method for an imaging module are further provided.