A holographic projector comprises an image processing engine arranged to, a hologram engine and a display engine. The image processing engine is arranged to receive a source image for projection. The source image comprises a first colour component and a second colour component. The image processing engine is further arranged to form a first colour secondary image from the first colour component by nulling alternate pixel values of the first colour component in accordance with a first checkerboard pattern. The image processing engine is further arranged to form a second colour secondary image from the second colour component by nulling alternate pixel values of the second colour component in accordance with a second checkerboard pattern. The first checkerboard pattern is opposite to the second checkerboard pattern. The hologram engine is arranged to determine a first colour hologram corresponding to the first colour secondary image and a second colour hologram corresponding to the second colour secondary image. The display engine is arranged to form a first colour holographic reconstruction from the first colour hologram and a second colour holographic reconstruction from the second colour hologram.

The present invention relates to a coherent detection array and methods of multiplexing for signal readout of the coherent detection array. The coherent detection array may be implemented on a photonic integrated circuit (PIC). It may comprise a plurality of coherent detection units coupling with connecting waveguides and electrical conducting paths, wherein the electrical conducting paths may manifest as readout channels for multiplexing electrical signals. The detection units may be configured to include free-space-to-waveguide couplers, optical couplers, and photodetectors. The coherent detection array enables multiplexing methods that may leverage extra degrees of freedom of the coherent detection array. These methods may include those enabled by the local oscillator and those related to the properties and responses of the components of the PIC-based detection array.

A polarization diffraction element comprising a film including a liquid crystalline material having photosensitivity, the film having at least one hologram recorded therein, and thereby having a property as a fork-shaped polarization grating having an anisotropic structure in which an optical axis continuously rotates toward a direction of a grating vector.

Techniques for displaying an input image in improved perceived resolution are described. In one aspect, a circuit is designed to include a set of memory cells, a horizontal decoder and a vertical decoder. An input image is received at an interface to the memory, the input is expanded into two separate frames in the memory, where the size of each of the two frames is identical to that of the input image. Image data in at least one of the two frames are modulated in amplitude and/or in phase. The first and second frames are then read out or displayed alternatively at twice the refresh rate originally set for the input image to achieve the perceived resolution.

A beam steering method and device are provided. The beam steering method includes outputting, from a hologram recording medium on which a plurality of signal light beams having different steering information are recorded, signal light beam having specific steering information, by making reference light having a specific characteristic incident on the hologram recording medium. The method further includes o obtaining information about an object existing in the external environment based on the output signal light.

A system includes a plurality of optical identifiers and a reader for the optical identifiers. Each optical identifier has an optical substrate and a volume hologram (e.g., with unique data, such as a code page) in the optical substrate. The reader for the optical identifiers includes a laser, and a camera. The laser is configured to direct laser light into a selected one of the optical identifiers that has been placed into the reader to produce an image of the associated volume holograms at the camera. The camera is configured to capture the image. The captured image may be stored in a digital format by the system.

An optical device including a first rigid substrate, a flexible holographic optical element, a transparent flexible material having a variable shear transmission property across an in-plane direction of the flexible holographic optical element, and a second rigid substrate, where the flexible holographic optical element and the transparent flexible material are located between the first and second rigid substrates, where the variable shear transmission property of the transparent flexible material transmits variable amounts of a shear force applied to the first or second rigid substrates across the in-plane direction of the flexible holographic optical element.

A holographic security or identification device (10) comprises an object, or a flexible substrate (12) configured to be conformable to a desired, curved shape; and a plurality of structures (14) formed on or in the object to have a desired curved configuration, or formed in or associated with the substrate and arranged to adopt a desired curved configuration when the substrate is conformed to a desired shape, wherein the plurality of structures (14) are configured to receive light (20) of a selected at least one wavelength or range of wavelengths and to produce, using the received light, a desired holographic image (22) for security or identification purposes when in the desired configuration.

A label-free bio-aerosol sensing platform and method uses a field-portable and cost-effective device based on holographic microscopy and deep-learning, which screens bio-aerosols at a high throughput level. Two different deep neural networks are utilized to rapidly reconstruct the amplitude and phase images of the captured bio-aerosols, and to output particle information for each bio-aerosol that is imaged. This includes, a classification of the type or species of the particle, particle size, particle shape, particle thickness, or spatial feature(s) of the particle. The platform was validated using the label-free sensing of common bio-aerosol types, e.g., Bermuda grass pollen, oak tree pollen, ragweed pollen, Aspergillus spore, and Alternaria spore and achieved >94% classification accuracy. The label-free bio-aerosol platform, with its mobility and cost-effectiveness, will find several applications in indoor and outdoor air quality monitoring.

Techniques for modulating both amplitude and phase via a layer of liquid crystals are described. According to one aspect of the techniques, a voltage being applied or coupled across the layer of liquid crystals is controlled by gradually increasing the voltage from a low level to a high level to perform the AM in a first range and the PM in second range, where the characteristics of the liquid crystals is significant, for example, by increasing the thickness or optical birefringence of the layer of liquid crystals.