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.

An interference imaging device includes a light interference generator that includes: a light wave splitter configured to reflect a part of incident light and to allow a remaining part of the incident light to pass through; a phase modulator configured to modulate a phase of incident light that has passed through the light wave splitter; and a reflector configured to reflect the phase-modulated incident light from the phase modulator so that the reflected, phase-modulated incident light overlaps with incident light that has been reflected by the light wave splitter.

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.

A low-cost digital holography microscope (DHM) that is capable of performing inspection at high speed while accurately inspecting an inspection object at high resolution, an inspection method using the DHM, and a method of manufacturing a semiconductor device by using the DHM are provided. The DHM includes: a light source configured to generate and output light; a beam splitter configured to cause the light to be incident on an inspection object and output reflected light from the inspection object; and a detector configured to detect the reflected light, wherein, when the reflected light includes interference light, the detector generates a hologram of the interference light, and wherein no lens is present in a path from the light source to the detector.

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.

Techniques related to generating holographic images are discussed. Such techniques include application of a hybrid system including a pre-trained deep neural network and a subsequent iterative process using a sui table propagation model to generate diffraction pattern image data for a target holographic image such that the diffraction pattern image data is to generate a holographic image when implemented via a holographic display.

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.

An optical device (100) for forming a distribution of a three-dimensional light field comprises: an array (102) of unit cells (104), a unit cell (104) being individually addressable for switching the optical property of the unit cell (104) between a first and a second condition; wherein the unit cells (104) are configured to be selectively active or inactive and wherein the array (102) comprises at least a first and a second disjoint subset (110; 112; 114; 116), and wherein the unit cells (104) in a subset (110; 112; 114; 116) are configured to be jointly switched from inactive to active, wherein the active unit cells (104) are configured to interact with an incident light beam (106) for forming the distribution of the three-dimensional light field; and wherein the optical device (100) is configured to address inactive unit cells (104) for switching the optical property of unit cells (104).

A computer calculates interference fringe phase estimated value data (30) of a phase-restored object image by performing iterative approximation calculation using interference fringe intensity data (10) measured by a digital holography apparatus and interference fringe phase initial value data (20), which is an estimated initial phase value of the image of the object. The interference fringe phase initial value data (20) is calculated by an initial phase estimator (300). The initial phase estimator (300) is constructed by implementing machine learning using interference fringe intensity data and the like for learning. The computer acquires reconfigured intensity data (40) and reconfigured phase data (50) by performing optical wave propagation calculation using the interference fringe phase estimation value data (30) of the image of the object acquired through phase restoration, and the interference fringe intensity data (10) used as input data for the initial phase estimator (300). This provides an iterative approximation calculation method and the like capable of making an initial value of a solution used in the iterative approximation calculation method a value close to the true value.

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.