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.

Optical systems having comb-shifted sets of holograms across different regions of a grating medium are disclosed. A first set of holograms may be formed in a first region of the grating medium and a second set of holograms may be formed in a second region of the grating medium. Each of the holograms in the first set may have a different respective grating frequency from a first set of grating frequencies. Each of the holograms in the second set may have a different respective grating frequency from a second set of grating frequencies. The second set of grating frequencies may be located within adjacent frequency gaps between the grating frequencies in the first set of grating frequencies. Comb-shifted sets of holograms may be used to perform pupil equalization, output coupling, input coupling, cross coupling, or other operations.

Optical systems having comb-shifted sets of holograms across different regions of a grating medium are disclosed. A first set of holograms may be formed in a first region of the grating medium and a second set of holograms may be formed in a second region of the grating medium. Each of the holograms in the first set may have a different respective grating frequency from a first set of grating frequencies. Each of the holograms in the second set may have a different respective grating frequency from a second set of grating frequencies. The second set of grating frequencies may be located within adjacent frequency gaps between the grating frequencies in the first set of grating frequencies. Comb-shifted sets of holograms may be used to perform pupil equalization, output coupling, input coupling, cross coupling, or other operations.

Provided is a multi-image display apparatus including a light source configured to emit light, a spatial light modulator configured to provide a first image by modulating the light emitted from the light source, and an optical system configured to transmit the first image provided by the spatial light modulator to a viewer, wherein the optical system is configured such that a travelling path of the first image provided by the spatial light modulator includes a first optical path in a first direction, a second optical path in a second direction orthogonal to the first direction, and a third optical path in a third direction orthogonal to the first direction and the second direction, respectively, and wherein the optical system is configured such that the first image and a second image provided from an optical path different from the travelling path of the first image are provided to the viewer.

Provided is a multi-image display apparatus including a light source configured to emit light, a spatial light modulator configured to provide a first image by modulating the light emitted from the light source, and an optical system configured to transmit the first image provided by the spatial light modulator to a viewer, wherein the optical system is configured such that a travelling path of the first image provided by the spatial light modulator includes a first optical path in a first direction, a second optical path in a second direction orthogonal to the first direction, and a third optical path in a third direction orthogonal to the first direction and the second direction, respectively, and wherein the optical system is configured such that the first image and a second image provided from an optical path different from the travelling path of the first image are provided to the viewer.

A method of recording multiple holograms into a holographic recording medium includes exposing the medium to a first light to cause changes in a first refractive index of at least a portion of a first layer of the medium to write a first hologram in the first layer without changing a second refractive index of a second layer of the recording medium. The method also includes exposing the medium to a second light to cause changes in a second refractive index of at least a portion of the second layer to write a second hologram in the second layer. The first layer may include a first photo-polymerizable composition polymerizable by the first light, and the second layer may include a second photo-polymerizable composition polymerizable by the second light and not polymerizable by the first light.

Methods and systems for projecting wave fields use a diffusing medium, a wavefront shaper, an illumination source, and a control system. A system for projecting an object wave field into a projection volume includes a wave scatterer, a wave field projector configured to project a wave field onto the wave scatterer, and a controller coupled to the wave field projector. The controller is configured to cause the wave field projector to project a wave field that, upon interacting with the wave scatterer, is redirected to form an object wave field that forms a predetermined pattern in the projection volume.

Methods and systems for projecting wave fields use a diffusing medium, a wavefront shaper, an illumination source, and a control system. A system for projecting an object wave field into a projection volume includes a wave scatterer, a wave field projector configured to project a wave field onto the wave scatterer, and a controller coupled to the wave field projector. The controller is configured to cause the wave field projector to project a wave field that, upon interacting with the wave scatterer, is redirected to form an object wave field that forms a predetermined pattern in the projection volume.

An optical device having suppressed rainbow effect is provided. The optical device includes a light source configured to generate an image light, an optical combiner coupled with the light source and configured to direct the image light to an eye-box of the optical device, and a dimming element disposed at the optical combiner. The optical combiner includes at least one diffractive element. The optical combiner has a first side facing the eye-box and an opposing second side facing a real world, and the dimming element is disposed at the second side of the optical combiner. The dimming element is configured to receive a light from the real world and significantly attenuate an intensity of the light having an incidence angle in a predetermined range.

A method for large volume holographic imaging is provided that may include determining projection operators within sub-volumes of a decomposed target volume, and determining a point aggregation operator for each sub-volume based on the projection operators. The method may further include receiving holographic field measurement data set captured for the target volume via the sensor array, generating a sub-volume interest value for each sub-volume by applying the holographic field measurement data set to each point aggregation operator, determining a sub-volume with a highest sub-volume interest value, and determining respective lower-tier sub-volume interest values for lower-tier sub-volumes of the sub-volume with the highest sub-volume interest value. The lower-tier sub-volumes may be defined by decomposing the sub-volume with the highest sub-volume interest value. Additionally, the method may include generating an image of the target volume based on the lower-tier sub-volume interest values.