There is provided a holographic optical element including: a hologram portion including a plurality of groups of unit regions, each group of unit regions of the hologram portion being configured to produce a respective holographic image under a respective light illumination having a respective predetermined wavelength; and a colour filter portion formed on the hologram portion, the colour filter portion including a plurality of groups of unit regions, each group of unit regions of the colour filter portion being arranged on a corresponding group of the plurality of groups of unit regions of the hologram portion, whereby the plurality of groups of unit regions of the colour filter portion is spatially arranged to form a predetermined colour image. There is also provided a method of forming the holographic optical element. There is further provided an article having optical security incorporated therein.

A method of projecting a first image and a second image using one multi-wavelength hologram. The first image is different to the second image. The multi-wavelength hologram is arranged for illumination by light of a first wavelength to project the first image. The multi-wavelength hologram is further arranged for illumination by light of a second, shorter wavelength to project the second image.

A method of projecting a first image and a second image using one multi-wavelength hologram. The first image is different to the second image. The multi-wavelength hologram is arranged for illumination by light of a first wavelength to project the first image. The multi-wavelength hologram is further arranged for illumination by light of a second, shorter wavelength to project the second image.

Provided are methods for replication (copying) of volume Holographic Optical Elements (HOE) using a master hologram in optical contact with a prism, wherein the master hologram comprises distinct object and reference beam coupling elements, and wherein in the replication process light is coupled from one face of the prism and transmitted through another face of the prism using the distinct object and reference beam coupling elements. Methods for making the master hologram by sequentially forming the distinct object and reference beam coupling elements therein are provided. Further methods for encoding aperture functions directly to the master hologram are provided. Yet further methods provide for forming a copy HOE in an array configuration using a step-and-repeat method wherein the copy HOE is translated laterally by a specified distance before the next exposure is made.

An illumination device has a coherent light source that emits coherent light beam, and an optical device that diffuses the coherent light beam, wherein the optical device comprises a first diffusion region that diffuses the coherent light beam to illuminate a first area, and a second diffusion region that diffuses the coherent light beam to display predetermined information in a second area.

An illumination device has a coherent light source that emits coherent light beam, and an optical device that diffuses the coherent light beam, wherein the optical device comprises a first diffusion region that diffuses the coherent light beam to illuminate a first area, and a second diffusion region that diffuses the coherent light beam to display predetermined information in a second area.

A display engine arranged to generate patterns for display by a display device. The display engine is arranged to generate a pattern comprising a first pattern area comprising a first hologram of a first image for projection onto a first image plane and a first lens area of a first lens function having first optical power. The pattern further comprises a second pattern area comprising a second hologram of a second image for projection onto a second image plane and a first lens area of a second lens function having second optical power. The first optical power and the second optical power are different, such that the first image and second image are projected different distances from the pattern when the pattern is illuminated.

A display engine arranged to generate patterns for display by a display device. The display engine is arranged to generate a pattern comprising a first pattern area comprising a first hologram of a first image for projection onto a first image plane and a first lens area of a first lens function having first optical power. The pattern further comprises a second pattern area comprising a second hologram of a second image for projection onto a second image plane and a first lens area of a second lens function having second optical power. The first optical power and the second optical power are different, such that the first image and second image are projected different distances from the pattern when the pattern is illuminated.

A holographic display with an illumination device, an enlarging unit and a light modulator. The illumination device includes at least one light source and a light collimation unit, the light collimation unit collimates the light of the at least one light source and generates a light wave field of the light that is emitted by the light source with a specifiable angular spectrum of plane waves, the enlarging unit is disposed downstream of the light collimation unit, seen in the direction of light propagation, where the enlarging unit includes a transmissive volume hologram realising an anamorphic broadening of the light wave field due to a transmissive interaction of the light wave field with the volume hologram, and the light modulator is disposed upstream or downstream of the anamorphic enlarging unit, seen in the direction of light propagation.

A light projection apparatus is provided comprising: a source of light; a switchable grating on a first substrate; and a diffractive optical element. Light is diffracted at least once by the switchable grating and is diffracted at least once by the DOE.