A diffractive optical element for a structured light projection module and a method of using the diffractive optical element are described herein. The diffractive optical element is configured to: receive two-dimensional patterned beams and generate multi-order diffractive beams, wherein the two-dimensional patterned beams are emitted from a structured light projection module, the structured light projection module includes a light source comprising a plurality of sub-light sources arranged in a two-dimensional array, and the two-dimensional patterned beams correspond to the two-dimensional array; and project a plurality of two-dimensional patterned beams, wherein each of the plurality of two-dimensional patterned beams creates a corresponding duplicated pattern, and the duplicated patterns form a speckle pattern having uniform speckle density. The two-dimensional patterned beams can overlap with each other, or not overlap with each other.

An optical test method is provided. The optical test method includes emitting light through a gap between two substrates of a tested optical element disposed on a holder to generate a plurality of light beams. The optical test method further includes driving the holder with the tested optical element to move to N positions. The optical test method also includes receiving one of the light beams from the tested optical element in the N positions to generate N first intensity signals. In addition, the optical test method includes determining the size of the gap of the tested optical element according to the N first intensity signals and reference data.

An imaging device is presented for use in an imaging system capable of improving the image quality. The imaging device has one or more optical systems defining an effective aperture of the imaging device. The imaging device comprises a lens system having an algebraic representation matrix of a diagonalized form defining a first Condition Number, and a phase encoder utility adapted to effect a second Condition Number of an algebraic representation matrix of the imaging device, smaller than said first Condition Number of the lens system.

A grating coupler couples a waveguide to a beam and is formed of patterned shapes in a first and second layer of planar material, the shapes embedded in background material, the layers separated by less than one wavelength. The shapes are organized as a plurality of adjacent unit cells arranged along a direction of propagation of light with each unit cell including a shape of the first material and a shape of the second material, each unit cell having design parameters including a period, a width wb of the shape of first planar material, a width wt of the shape of second planar material, and an offset between the shapes. The coupler has a directivity ratio D is at least 10 dB between “up” and “down” radiation; and unit cells differ in at least one parameter selected from period, wb, wt, and offset to provide a predetermined beam shape.

An imaging device is presented for use in an imaging system capable of improving the image quality. The imaging device has one or more optical systems defining an effective aperture of the imaging device. The imaging device comprises a lens system having an algebraic representation matrix of a diagonalized form defining a first Condition Number, and a phase encoder utility adapted to effect a second Condition Number of an algebraic representation matrix of the imaging device, smaller than said first Condition Number of the lens system.

A three dimensional image measurement system including a first optical system and a second optical system is provided. The first optical system is adapted to output a structural light beam and a zero order light beam. There is an angle between the structural light beam and the zero order light beam. The first optical system performs an optical operation to project the structural light beam to a three dimensional object to obtain three dimensional information of the three dimensional object. The second optical system is adapted to receive the zero order light beam and perform another optical operation by using the zero order light beam. The first optical system includes a plurality of optical elements. The value of the angle between the structural light beam and the zero order light beam is determined according to position parameters of the optical elements.

An optical system, an electronic device, and a method for designing a diffractive optical element of an optical system are provided. The optical system comprises: a transparent display screen, comprising a plurality of periodically arranged pixel units for display; and a light emitting module, comprising a light source and a diffractive optical element, and configured to emit a patterned light beam outward through the transparent display screen. The diffractive optical element is configured to receive an incident light beam from the light source and project a first diffracted light beam, wherein the first diffracted light beam is incident on the transparent display screen and then diffracted again, such that the patterned light beam is projected outward. An electronic device, comprises the above optical system, and a filter unit disposed between the transparent display screen and the optical module, and configured to reduce passage of visible light from the transparent display screen.

A method of performing coherent transformations of optical fields includes forming a far field distribution of the input optical field. A fraction of the formed far field is diffracted by producing localized discontinuities within said far field. A Fraunhofer diffraction pattern of the diffracted optical field is formed. The Fraunhofer diffraction pattern is modified by producing localized optical path differences within the Fraunhofer diffraction pattern. The transformed output optical field is produced in the far field with respect to the modified Fraunhofer diffraction pattern.

An optical test method is provided. The optical test method includes emitting light through a gap between two substrates of a tested optical element disposed on a holder to generate a plurality of light beams. The optical test method further includes driving the holder with the tested optical element to move to N positions. The optical test method also includes receiving one of the light beams from the tested optical element in the N positions to generate N first intensity signals. In addition, the optical test method includes determining the size of the gap of the tested optical element according to the N first intensity signals and reference data.

A hologram is constructed from individual subholograms assigned to corresponding encoding regions in a light modulation device and respectively assigned to an object point of the object to be reconstructed with the hologram. With a virtual observer window, a defined viewing region is provided through which a reconstructed scene in a reconstruction space is observed by an observer. A complex value of a wavefront for each individual object point is calculated in the virtual observer window. Each individual amplitude of a complex value of a wavefront in the virtual observer window is subsequently multiplied by a correction value with which a correction of the angle selectivity of at least one volume grating arranged downstream in the beam path of the light modulation device is carried out. The corrected complex values determined in this way for all object points are summed and transformed into the hologram plane of the light modulation device.