A light detection and ranging, “LiDAR”, system arranged to make time of flight measurements of a scene. The LiDAR system comprises a holographic projector comprising: a spatial light modulator arranged to display light modulation patterns, each light modulation pattern comprising a hologram and a grating function having a periodicity; a light source arranged to illuminate each displayed light modulation pattern in turn; and a projection lens arranged to receive spatially modulated light from the spatial light modulator and project a structured light pattern corresponding to each hologram onto a respective replay plane. The LiDAR system further comprises a system controller arranged to receive distance information related to the scene and output to the holographic projector a control signal corresponding to the distance information. The holographic projector is arranged to use the control signal to determine a parameter for projection of a subsequent structured light pattern.

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.

The apertures typically used for hologram recording create unwanted secondary holograms by diffracting light. Aperture-free hologram recording eliminates these unwanted secondary holograms. Aperture-free hologram recording includes applying a mask to the holographic recording medium. The mask controls the size of the recorded hologram like an aperture but does not create unwanted secondary holograms. Hologram fringes are only present in the desired recording area and a thin boundary region. The mask may be present during recording, or the mask may be used to pre-bleach the holographic recording medium. Pre-bleaching the holographic recording medium renders a portion of the holographic recording medium insensitive to light, the hologram is recorded in the light-sensitive portions of the holographic recording medium.

The apertures typically used for hologram recording create unwanted secondary holograms by diffracting light. Aperture-free hologram recording eliminates these unwanted secondary holograms. Aperture-free hologram recording includes applying a mask to the holographic recording medium. The mask controls the size of the recorded hologram like an aperture but does not create unwanted secondary holograms. Hologram fringes are only present in the desired recording area and a thin boundary region. The mask may be present during recording, or the mask may be used to pre-bleach the holographic recording medium. Pre-bleaching the holographic recording medium renders a portion of the holographic recording medium insensitive to light, the hologram is recorded in the light-sensitive portions of the holographic recording medium.

A system for making a holographic medium for use in generating light patterns for eye tracking includes a light source configured to provide light and a beam splitter configured to separate the light into a first portion of the light and a second portion of the light that is spatially separated from the first portion of the light. The system also includes a first set of optical elements configured to transmit the first portion of the light for providing a first wide-field beam onto an optically recordable medium and one or more diffractive optical elements configured to receive the second portion of the light and project a plurality of separate light patterns onto the optically recordable medium for forming the holographic medium.

A method for observing a sample is placed between a light source and an image sensor, comprising at least 10000 pixels, the light source emits an illuminating beam, which propagates to the sample, the light beam is emitted in an illumination spectral band (Δλ.sub.11) lying above 800 nm, the method comprising the following steps: (a) illuminating the sample with the light source; (b) acquiring an image of the sample (I.sub.0) with the image sensor, no image-forming optics being placed between the sample and the image sensor; and (c) the image sensor being configured such that it has a detection spectral band (Δλ.sub.20), which blocks wavelengths in the visible spectral band, such that the image may be acquired in ambient light.

An optical device and an eye-tracking system to suppress a rainbow effect are provided. The optical device includes a grating. The grating includes at least one substrate and a grating structure coupled to the at least one substrate. The grating structure is configured to diffract an infrared light beam and transmit a visible light beam with a diffraction efficiency less than a predetermined threshold.

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.

There is provided a head-up display having an eye-box comprising a driver monitoring system, picture generating unit and optical system. The driver monitoring system is arranged to illuminate and monitor a driver. The driver monitoring system comprises a first display channel. The picture generating unit is arranged to display a picture on a replay plane. The picture generating unit comprises a second display channel Each display channel comprises a light source, spatial light modulator and controller. Each light source is arranged to emit light. Each spatial light modulator is arranged to receive light from the respective light source and output spatially-modulated light in accordance with a computer-generated hologram displayed on the spatial light modulator to form a respective light pattern on the replay plane. Each controller is arranged to output the computer-generated hologram to the spatial light modulator. The optical system is arranged to relay each light pattern from the replay plane. The optical system comprises an input, output and at least one mirror. The input is arranged to receive light of each light pattern. The output is arranged to output light of each light pattern. The at least one mirror is arranged to guide light from the input to the output along an optical path. The light pattern formed by the first display channel is an infrared light pattern. Each light pattern is a holographic reconstruction.

A light detection and ranging, “LiDAR”, system arranged to make time of flight measurements of a scene. The LiDAR system comprises a holographic projector comprising: a spatial light modulator arranged to display light modulation patterns, each light modulation pattern comprising a hologram and a grating function having a periodicity; a light source arranged to illuminate each displayed light modulation pattern in turn; and a projection lens arranged to receive spatially modulated light from the spatial light modulator and project a structured light pattern corresponding to each hologram onto a respective replay plane. The LiDAR system further comprises a system controller arranged to receive distance information related to the scene and output to the holographic projector a control signal corresponding to the distance information. The holographic projector is arranged to use the control signal to determine a parameter for projection of a subsequent structured light pattern.