A method for observing a sample includes illuminating the sample with a light source and forming a plurality of images, by an imager, the images representing the light transmitted by the sample in different spectral bands. From each image, a complex amplitude representative of the light wave transmitted by the sample is determined in a determined spectral band. The method further includes backpropagation of each complex amplitude in a plane passing through the sample, determining a weighting function from the back-propagated complex amplitudes, propagating the weighting function in a plane along which the matrix photodetector extends, updating each complex amplitude, in the plane of the sample, according to the weighting function propagated.

A focus modulation optical system and a holographic display device having the focus modulation optical system are disclosed. The holographic display device includes a light source configured to emit a plurality of color lights, a focus modulation optical system including at least one variable focus lens that is configured to change a focusing position of incident light by electrical control of the at least one variable focus lens based on a color of light incident on the variable focus lens, and a spatial light modulator configured to form a holographic image by diffracting light output from the focus modulation optical system.

There is provided a device allowing a sample to be observed in a first mode, by lensless imaging using a first sensor. The first mode allows a first image to be obtained, on the basis of which a region of interest of the sample may be identified. The device then allows, via a relative movement, the region of interest to be analyzed using a more precise second mode and in particular using an optical system coupled to a second sensor.

A method for generating a holographic image, a signal processor, a holographic image display device, a wearable apparatus, and an onboard head-up display apparatus. The method comprises: performing holographic transformation on the basis of a target amplitude phase distribution of a target image to obtain a holographic phase image; performing phase quantization of the holographic phase image to obtain a quantized holographic image; performing inverse holographic transformation of the quantized holographic image to obtain a reconstructed image; if the reconstructed image satisfies a preset condition, determining that the quantized holographic image is a target holographic image; if not, constraining the amplitude phase of the reconstructed image and, on the basis of the amplitude phase constrained image, continuing iteration. The present method can rapidly and effectively implement monochrome or multi-colour high contrast ratio, low noise real-time holographic image generation and display, and the imaging distance can be freely adjusted.

A holographic display device includes a light source configured to emit light, the light including first light of a first wavelength, second light of a second wavelength, and third light of a third wavelength; a spatial light modulator configured to form a holographic pattern to modulate the light emitted from the light source and to produce a holographic image; and a focusing optical system configured to focus the holographic image. The focusing optical system includes a fixed-focus optical system having a fixed focal length, and a variable focus optical system having a focal length that is changed by electrical control. The fixed-focus optical system is configured to focus the first light of the first wavelength, the second light of the second wavelength, and the third light of the third wavelength on different positions, respectively, on an optical axis to cancel a chromatic aberration by the variable focus optical system.

A display system comprising a first plurality of pixels, a second plurality of pixels, a first Fourier transform lens and a second Fourier transform lens. The first plurality of pixels is arranged to display first holographic data corresponding to a first holographic reconstruction and receive light of a first wavelength. The a second plurality of pixels is arranged to display second holographic data corresponding to a second holographic reconstruction and receive light of a second wavelength. The first Fourier transform lens is arranged to receive spatially modulated light having a first wavelength from the first plurality of pixels and perform an optical Fourier transform of the received light to form the first holographic reconstruction at a replay plane, wherein the first holographic reconstruction is formed of light at the first wavelength. The second Fourier transform lens is arranged to receive spatially modulated light having a second wavelength from the second plurality of pixels and perform an optical Fourier transform of the received light to form the second holographic reconstruction at the replay plane, wherein the second holographic reconstruction is formed of light at the second wavelength. The optical path length from the first Fourier transform lens to the replay plane is not equal to the optical path length from the second Fourier transform lens to the replay plane.

A predetermined lighting pattern is projected on a surface to be illuminated and the lighting pattern is displaced on the surface to be illuminated. A laser beam generated by a laser light source is broadened by a magnifying lens so as to generate a divergent light. The divergent light is shaped by the collimation lens into a parallel illumination light, and the parallel illumination light is caused to be incident on an incident plane of a diffraction optical element which records a hologram image. A diffracted light from the diffraction optical element forms the lighting pattern as a hologram reconstructed image on the surface to be illuminated. By translating the collimation lens by a collimation-lens drive unit along a movement plane that is orthogonal to an optical axis of the laser beam, the lighting pattern can be displaced on the surface to be illuminated.

There is provided a holographic projector comprising a hologram engine and a controller. The hologram engine is arranged to provide a hologram comprising a plurality of hologram pixels. Each hologram pixel has a respective hologram pixel value. The controller is arranged to selectively-drive a plurality of light-modulating pixels so as to display the hologram. Displaying the hologram comprises displaying each hologram pixel value on a contiguous group of light-modulating pixels of the plurality of light-modulating pixels such that there is a one-to-many pixel correlation between the hologram and the plurality of light-modulating pixels.

A digital holographic image-taking apparatus includes an illumination portion having a light emission surface for emitting illumination light toward an object, the illumination light having a specific wavelength in a coherent plane waveform; and an image sensor having an pixel array including two-dimensionally arranged pixels, the image sensor capturing an interference pattern generated based on the illumination light having acted on the object, in which the following conditional expression is satisfied: 0.0000001<Z.sup.2/S<16, where S represents the area of the light emission surface, and Z represents the distance from the light emission surface to the pixel array.

Embodiments of the present disclosure include apparatuses and method for a stacked light emitting diode (LED) hologram display. A stacked LED hologram display can include a first array of LEDs that are configured to emit red light received by a meta-optics panel configured to display a first portion of a holographic image, a second array of LEDs that are configured to emit green light received by a meta-optics panel configured to display a second portion of a holographic image, and a third array of LEDs that are configured to emit blue light received by a meta-optics panel configured to display a third portion of a holographic image. The stacked LED hologram display can include a number of actuators configured to adjust a position of a first array of LEDs in first direction and a second direction, adjust a position of a second array of LEDs in the first direction and the second direction, and adjust a position of a third array of LEDs in the first direction and the second direction.