Systems, devices, and methods for aperture-free hologram recording are described. 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.

Systems, devices, and methods for aperture-free hologram recording are described. 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.

Systems, devices, and methods for aperture-free hologram recording are described. 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 digital holographic apparatus includes a first hologram generating unit that generates a first hologram by causing first object light in a first observation direction to interfere with first reference light, the first object light being generated by irradiating an observation object with light having a first wavelength, the first reference light being derived from the light having the first wavelength; a second hologram generating unit that generates a second hologram by causing second object light in a second observation direction that differs from the first observation direction to interfere with second reference light, the second object light being generated by irradiating the observation object with light having a second wavelength, the second reference light being derived from the light having the second wavelength; a first image capturing unit that captures the first hologram; and a second image capturing unit that captures the second hologram.

A generation method of a digital hologram includes steps of emitting coherent light from a coherent light source, imaging a hologram that is an interference pattern of an object beam and a reference beam due to the emission light from the light source, and setting a plurality of wavelengths of the illumination light that generates the hologram detected by the detector, and wherein the plurality of wavelength are specified by the wavelength setting step based on a magnification percentage X of a conjugate image set up by a user not to disturb visibility of an image when a real image and the conjugate image reconstructed by a predetermined calculation means relative to structures of observation targets are superimposed to a corresponding real image so that a shortest wavelength .sub.min and a longest wavelength .sub.max satisfy the expression .sub.max/.sub.min(1/X+1).

An optical reflective device referred to as a skew mirror, having a reflective axis that need not be constrained to surface normal, is described. Examples of skew mirrors are configured to reflect light about a constant reflective axis across a relatively wide range of wavelengths. In some examples, a skew mirror has a constant reflective axis across a relatively wide range of angles of incidence. Exemplary methods for making and using skew mirrors are also disclosed. Skew mirrors include a grating structure, which in some examples comprises a hologram.

Systems, devices, and methods for eyebox expansion by exit pupil replication in wearable heads-up displays (WHUDs) are described. A WHUD includes a scanning laser projector (SLP), a holographic combiner, and an optical splitter positioned in the optical path therebetween. The optical splitter receives light signals generated by the SLP and separates the light signals into N sub-ranges based on the point of incidence of each light signal at the optical splitter. The optical splitter redirects the light signals corresponding to respective ones of the N sub-ranges towards the holographic combiner effectively from respective ones of N spatially-separated virtual positions for the SLP. The holographic combiner converges the light signals to respective ones of N spatially-separated exit pupils at the eye of the user. In this way, multiple instances of the exit pupil are distributed over the area of the eye and the eyebox of the WHUD is expanded.

An optical device including a first rigid substrate, a flexible holographic optical element, a transparent flexible material having a variable shear transmission property across an in-plane direction of the flexible holographic optical element, and a second rigid substrate, wherein the flexible holographic optical element and the transparent flexible material are located between the first and second rigid substrates, wherein the variable shear transmission property of the transparent flexible material transmits variable amounts of a shear force applied to the first or second rigid substrates across the in-plane direction of the flexible holographic optical element.

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.

Systems, devices, and methods for side lobe control in holograms are described. The magnitude of the side lobes of a hologram depends on the distribution of refractive index modulation (?n), therefore control of side lobe magnitude may be achieved by controlling the distribution of ?n. The distribution of ?n may be controlled by replicating a hologram from a master with two reference beams, where the wavelength and angle of each reference beam, the playback angle of the master hologram, and the thickness of the master hologram, the copy holographic recording medium (HRM), and the recording substrate are carefully chosen to achieve a pattern of meta-interference within the HRM that matches the desired distribution of ?n.