A system includes a mask configured to forwardly diffract an input beam as a first set of two polarized beams. The system also includes a polarization conversion element configured to convert the first set of two polarized beams into a second set of two polarized beams having opposite handednesses. The two polarized beams having opposite handednesses interfere with one another to generate a polarization interference pattern.

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.

Transmission and reflection mode VHOEs are designed and fabricated for use in imaging and other applications. These VHOE provide high diffraction efficiency with minimal chromatic aberrations and astigmatism across the bandwidth. The lens provides optical power within the bandwidth centered relative to several wavelengths to magnify (focus or collimate) input light and is transparent for the rest of the image spectrum. In transmission mode, two VHOE are fabricated in such a way as to introduce compensating adjustments that minimize the astigmatism and chromatic aberrations introduced by the bandwidth of the input light. Two VHOEs are required to provide an on-axis imaging system to magnify light to form an image and reduce the chromatic aberrations across the bandwidth and reduce the astigmatism while maintaining high diffraction efficiency (DE). In reflection mode, a single VHOE is configured to act as a mirror at the specified wavelength and bandwidth and to magnify light to form an image and, consequently, has minimal level of astigmatism and chromatic aberration.

A method for optimally producing a holographic image using a Holographic Optical Element (HOE) and the HOE meant for controlling directions and divergences of light beams to impart system compactness. The system uses concave and convex lenses and other beam expanding, splitting, modulating and combining optics for realization of compactness and high throughput. The thin laser beam is split using a holographic optical element and a conventional beam splitter. A neutral density filter adjusts the intensity of a reference beam to match the intensity of an object beam so that high quality digital holograms can be recorded. Effects of vibrations are minimized by the compact optical design, by anti-vibration mounts, by mounting all the opto-mechanical components on a single rigid platform and by enclosing the system. An electro-optical sensor array records holograms digitally and an algorithm numerically reconstructs and further quantifies the results using a personal computer/laptop/tablet etc.

A method of forming a filter, comprising the steps of: selecting at least a first wavelength corresponding to a predetermined laser threat and having a first colour in the visible spectrum; providing a generally transparent substrate and forming a first notch filter region therein configured to substantially block incident radiation thereon of wavelengths within a first predetermined wavelength band including said first wavelength; selecting a second wavelength having a second colour in the visible spectrum and forming a colour balancing notch filter region in said substrate configured to block incident radiation thereon of wavelengths within a wavelength band including said second wavelength, thereby to balance or neutralise any colour distortion of said substrate caused by said first notch filter region.

The present invention suggests a holographic optical element which forms a pattern according to a transmissive hologram recording method based on a multi-diverging object beam and a reference beam, a method for generating the same, and a screen device including the holographic optical element. The holographic optical element according to the present invention includes a base film and a pattern which is formed on the base film by using a transmissive hologram recording method based on a multi-diverging object beam and a reference beam.

A system for making a holographic medium 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, a second set of optical elements configured to transmit the second portion of the light for providing a second wide-field beam, and a plurality of prisms optically coupled with the second set of optical elements and configured to receive the second wide-field beam and project a plurality of separate light patterns onto the optically recordable medium for forming the holographic medium.

Techniques disclosed herein relate generally to eye-tracking in near-eye display systems. One example of an eye illuminator for eye-tracking includes a substrate transparent to visible light, an array of light sources immersed in the substrate and configured to emit infrared light, and a holographic optical element conformally coupled to a surface of the substrate and encapsulated by an encapsulation layer. The holographic optical element is configured to transmit the visible light and diffract the infrared light emitted by the array of light sources to the eye of a user for eye-tracking.

An eye-tracking system includes a holographic illuminator and a detector. The holographic illuminator includes a light source configured to provide light and a holographic medium optically coupled with the light source. The holographic medium is configured to receive the light provided from the light source and concurrently project a plurality of separate light patterns toward an eye. The detector is configured to detect a reflection of at least a subset of the plurality of separate light patterns, reflected off the eye, for determining a location of a pupil of the eye. Also disclosed is a method for determining a location of a pupil of an eye with the eye-tracking system that includes the holographic illuminator.

An additive manufacturing device may include a material supply, a robot, and a printing head coupled to a distal end of the robot and configured to receive printing material from the material supply. The additive manufacturing device may have an IR holographic device configured to generate a targeting hologram, an IR sensor, and a controller coupled to the robot, the printing head, the IR holographic device, and the IR sensor. The controller may be configured to cause the printing head to dispense the printing material to form an object based upon the targeting hologram.