Provided is a digital holographic image-taking apparatus, including: an illumination portion (10) having a light emission surface (14D) for emitting illumination light toward an object (1), the illumination light having a specific wavelength in a coherent plane waveform; and an image sensor (50) having an pixel array (51) including two-dimensionally arranged pixels, the image sensor (50) capturing an interference pattern generated based on the illumination light having acted on the object (1), 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 (14D), and Z represents the distance from the light emission surface (14D) to the pixel array (51).

A metamaterial optical filter including: a transparent substrate; and a photosensitive polymer layer provided to the transparent substrate, wherein the photosensitive polymer layer is treated using a laser to form a non-conformal holographically patterned subwavelength grating, the holographic grating configured to block a predetermined wavelength of electromagnetic radiation. A system and method for manufacturing holographically patterned subwavelength grating onto the photosensitive polymer layer including: applying a photosensitive polymer layer to a transparent substrate; placing the photosensitive polymer layer between a laser and a mirror; scanning the laser over the photosensitive polymer layer such that a holographic grating is created within the photosensitive polymer layer by interaction between the laser light and light reflected from the mirror; and stacking two or more holographically patterned subwavelength grating layers to form complex metamaterial optical filter stacks.

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.

Methods, apparatus, devices, and systems for displaying three-dimensional objects by individually diffracting different colors of light are provided. In one aspect, an optical device includes: a first optically diffractive component including a first diffractive structure configured to diffract a first color of light having a first incident angle at a first diffracted angle, a second optically diffractive component including a second diffractive structure configured to diffract a second color of light having a second incident angle at a second diffracted angle, a first reflective layer configured to totally reflect the first color of light having the first incident angle and transmit the second color of light, and a second reflective layer configured to totally reflect the second color of light having the second incident angle. The first reflective layer is between the first and second diffractive structures, and the second diffractive structure is between the first and second reflective layers.

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.

Methods, apparatus, devices, subsystems, and systems for holographically displaying three-dimensional objects are provided. In one aspect, an optical device includes: a first optically diffractive component including a first diffractive structure configured to diffract a first color of light having a first incident angle at a first diffracted angle, a second optically diffractive component including a second diffractive structure configured to diffract a second color of light having a second incident angle at a second diffracted angle, a first reflective layer configured to totally reflect the first color of light having the first incident angle and transmit the second color of light, and a second reflective layer configured to totally reflect the second color of light having the second incident angle. The first reflective layer is between the first and second diffractive structures, and the second diffractive structure is between the first and second reflective layers.

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.

Provided is a holographic display apparatus capable of providing an expanded viewing window when reproducing a holographic image via an off-axis technique. The holographic display apparatus includes a spatial light modulator comprising a plurality of pixels arranged two-dimensionally; and an aperture enlargement film configured to enlarge a beam diameter of a light beam coming from each of the plurality of pixels of the spatial light modulator. The beam diameter of each light beam enlarged by the aperture enlargement film may be greater than the width of an aperture of each pixel of the spatial light modulator.