A method for producing a holographic optical element (HOE) that is provided for projection in a projection system. A hologram is recorded by the fact that a first Gaussian beam and a second Gaussian beam are caused to interfere on a holographic film for at least two different configurations. The first Gaussian beam is a reference beam that, for the at least two different configurations, is identical to a reconstruction beam with which the HOE is reconstructed. The second Gaussian beam is furthermore an object beam that, upon reconstruction of the HOE utilizing the reconstruction beam, is identical to a projection beam that is used in the projection system for projection. For the at least two different configurations, at least one beam property that depends respectively on predefined projection properties of the projection system is predefined for the second Gaussian beam.

There are provided volume holograms and combinations of lenticular lenses and holograms in particular for security applications. In embodiments, a volume hologram comprises a holographic medium (102) including a first optical interference structure which, upon illumination, replays a first image (110); wherein the first image includes a lenticular lens layer (111) including an array of lenticules and a lenticular image layer (113) including first (114) and second (115) interlaced images corresponding with the array of lenticules.

A diffractive structure arranged to spatially modulate light transformable by a viewing system into a target image. The diffractive structure is configured to generate a plurality of discrete light patterns. Each light pattern corresponds to a different part of the target image. The shape of each discrete light pattern substantially corresponds to the shape of an entrance aperture of the viewing system.

A holographic optical element, a method for manufacturing the same and an apparatus for producing the same are provided. More particularly, the holographic optical element is capable of enhancing the brightness of an augmented image. In one example, the holographic optical element includes a plurality of optical elements combined together and has interference patterns recorded on the plurality of optical elements, respectively. The interference patterns have the same pitch and different inclination angles

A light engine arranged to form an image visible from a viewing window. The light engine comprises: a display device arranged to display a hologram of the image and spatially modulate light in accordance with the hologram; a hologram replicator arranged to receive the spatially modulated light and provide a plurality of different light propagation paths for the spatially modulated light from the display device to the viewing window; and a control device disposed in an optical path between the first replicator and the second replicator. The control device is angled such that light from the first replicator is incident at an acute angle on the control device, and each cell of the array is switchable between a first state and a second state.

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 dark field digital holographic microscope and associated metrology method is disclosed which is configured to determine a characteristic of interest of a structure. The dark field digital holographic microscope includes an illumination branch for providing illumination radiation to illuminate the structure; a detection arrangement for capturing object radiation resulting from diffraction of the illumination radiation by the structure; and a reference branch for providing reference radiation for interfering with the object radiation to obtain an image of an interference pattern formed by the illumination radiation and reference radiation. The reference branch has an optical element operable to vary a characteristic of the reference radiation so as to reduce and/or minimize variation in a contrast metric of the image within a field of view of the dark field digital holographic microscope at a detector plane.

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.

A control device includes a processor. The processor acquires positional information indicating a position of an observation target. The processor sets, from among a plurality of irradiation positions, a required irradiation position, which is an irradiation position corresponding to the position of the observation target indicated by the positional information and is an irradiation position required for obtaining a plurality of the interference fringe images that are sources of a super-resolution interference fringe image having a resolution exceeding a resolution of an imaging element. The processor causes a light source to emit an illumination light from the required irradiation position by controlling an operation of the light source, and causes the imaging element to outputs the interference fringe image at each required irradiation position.