A holographic display device includes a backlight unit for emitting light and a spatial light modulator. The spatial light modulator includes a plurality of pixels and a color filter layer including a plurality of color filter groups. The pixels are arranged in a zigzag form and are configured to modulate at least one of the amplitude and phase of the light. Each of the color filter groups includes a first sub-group including a plurality of first color filters, a second sub-group including a plurality of second color filters, and a third sub-group including a plurality of third color filters, and each of the pixels is aligned with one of the first color filters, the second color filters, and the third color filters of the color filter layer.

A method of generating a color image of a sample includes obtaining a plurality of low resolution holographic images of the sample using a color image sensor, the sample illuminated simultaneously by light from three or more distinct colors, wherein the illuminated sample casts sample holograms on the image sensor and wherein the plurality of low resolution holographic images are obtained by relative x, y, and z directional shifts between sample holograms and the image sensor. Pixel super-resolved holograms of the sample are generated at each of the three or more distinct colors. De-multiplexed holograms are generated from the pixel super-resolved holograms. Phase information is retrieved from the de-multiplexed holograms using a phase retrieval algorithm to obtain complex holograms. The complex hologram for the three or more distinct colors is digitally combined and back-propagated to a sample plane to generate the color image.

A holographic display apparatus for providing an expanded viewing window includes a spatial filter configured to separate a plurality of holographic images generated by the hologram pattern displayed on the spatial light modulator from a plurality of lattice spots generated by a physical structure of the spatial light modulator. The spatial filter includes a plurality of color filters or a plurality of dichroic mirrors separating a first color image, a second color image, and a third color image from a first color lattice spot, a second color lattice spot, and a third color lattice spot.

In the present invention, by providing an apparatus for displaying a hologram including: a beam source configured to output a plurality of beams, a spatial light modulator configured to include a plurality of SLM (spatial light modulator) regions, display a hologram, and diffract the plurality of beams; a plurality of front lenses each corresponding to the plurality of SLM regions, and configured to refract the plurality of beams diffracted from each of the plurality of SLM regions; a plurality of filters each corresponding to the plurality of SLM regions, and configured to filter a part of the plurality of refracted beams; and a plurality of back lenses each corresponding to the plurality of SLM regions, and configured to display an interference image corresponding to the hologram using the filtered part beam, the beam path of the hologram displaying apparatus can be drastically reduced, and an entire size of the hologram displaying apparatus can be reduced, so that it is possible to down-size the digital hologram display system.

According to the present invention, by providing a hologram displaying apparatus including a light source configured to output a plurality of lights of different wavelengths in a first direction, a generator configured to generate a plurality of color holograms of different wavelengths using the plurality of light, and output the plurality of color holograms in the first direction, a filter configured to filter an effective hologram which is an element of an effective band of the plurality of color holograms in the first direction, and a display configured to transmit the effective hologram in the first direction and display the effective hologram in space in the first direction, it is possible to effectively filter an effective band of a certain diffraction order of each color hologram forming a composing hologram.

To provide a display device capable of further improving reliability of the display device with respect to manufacturing variations, wavelength variations of light sources, and active variations (variations due to external factors). There is provided a display device including at least a light source, a first hologram, and a second hologram, in which the first hologram compensates for dispersion of light emitted from the light source and diffracts and emits the light, the second hologram diffracts the light diffracted with compensated dispersion, and emits the light in a direction of a pupil of a user, and the first hologram has an intensity distribution of different diffraction efficiency with respect to a wavelength of the light emitted from the light source depending on a position in a plane of the first hologram.

An optical system comprises an imaging holographic optical element, which produces a floating hologram. An upstream light-forming holographic optical element causes spectral filtering of the light.

A complex light modulator including a first polarization plate, a second polarization plate provided, an amplitude modulator provided between the first polarization plate and the second polarization plate, a phase modulator provided between the amplitude modulator and the second polarization plate, and color filters provided between the amplitude modulator and the phase modulator.

In some implementations, a method comprises: determining a set of characteristics of light spectra reflected or transmitted by a set of materials when the set of materials is illuminated by a plurality of light wavelengths; constructing one or more classifiers configured to classify each material of the set of materials based on the set of characteristics of the light spectra; using the classifiers, mapping each of the light spectra onto an area of an image sensor; wherein one or more optical elements filter and focus the light spectra onto one or more elements of a detector array; wherein each optical element focuses onto an area of the detector array; wherein the mapping is a 1:1 mapping; wherein each optical element uses a Bragg reflection condition to filter the light spectra and to focus the light spectra onto an element of the detector array.

A method for aquatic microplastic identification is provided. The method includes steps as follows: emitting a laser beam from a laser source, such that the laser beam passes through a liquid sample with MP samples in a sample channel and then a polarizer and is received by polarization camera; capturing a sample image of the MP samples by the polarization camera, wherein the sample image comprises interference patterns resulting from superposition of object and reference waves; and feeding the interference patterns into a morphology analyzing module for real-time tracking and analyzing by using a lightweight convolutional neural network (CNN) model, so as to classify the MP samples.