7 results about "Object wave" patented technology

A method of controlling a reconfigurable intelligent surface (RIS) is provided for multi-target spot beamforming at a plurality of target beam focus positions. The RIS includes a 2D array of unit cells, each unit cell being controllable to be at any selected one of a plurality of wave propagation path states for providing a corresponding degree of phase shift for an incident electromagnetic wave irradiated thereon. The method includes: for each of the plurality of target beam focus positions: determining, for each unit cell of the plurality of the 2D array of unit cells, an interference pattern at the unit cell between a reference wave from a multi-mode orbital angular momentum (OAM) signal transmitter to the unit cell and an object wave from the target beam focus position to the unit cell, the multi-mode OAM signal transmitter being configured to generate and transmit a multi-mode OAM signal to irradiate the RIS at a surface thereof; and for each unit cell of the plurality of the 2D array of unit cells: determining a holograph pattern based on the interference patterns determined at the unit cell for the plurality of target beam focus positions; determining a degree of phase shift for the unit cell to provide based on the holograph pattern determined for the unit cell; and controlling the unit cell to be at a selected one of the plurality of wave propagation path states corresponding to the degree of phase shift determined for the unit cell to provide. There is also provided a corresponding RIS controller and a corresponding multi-target spot beamforming system.

The application provides a large-size hologram fast generation method based on wave front recording plane optimization. The method comprises three steps: in the first step, a 3D object is discretized into point sources, a central diffraction diagram of each depth plane is calculated based on a scalar diffraction theory and a viewing zone characteristic, a diffraction diagram of other object points on the same layer is obtained by translating the central diffraction diagram, and a hologram of the wave front recording plane of the 3D object is obtained by superimposing diffraction diagrams of all object points; in the second step, diffraction from the wave front recording plane to a holographic surface is calculated based on an angular spectrum diffraction theory, and a hologram of the 3D object on the holographic surface is obtained; and in the third step, the obtained hologram is segmented and zero-filled to obtain a hologram 1 and a hologram 2, digital blazed gratings are loaded on the two holograms to obtain two final holograms, the two final holograms are loaded on two spatial light modulators, effective imaging areas of the two spatial light modulators are spliced together by means of a beam splitter, and a large-size object reconstruction image is obtained.

An interferometer for the measurement of a surface or an optical thickness of an optically smooth test object is provided, wherein the interferometer is configured to illuminate the optically smooth test object simultaneously with a plurality of object waves, which have different wavelengths from one another, and to superimpose the object waves deformed by the illuminated test object onto coherent reference waves on an image capture device, and to spectrally decompose the interferograms resulting from the superposition into wavelength-specific partial interferograms.

An interferometer (10) is provided for measuring the surface (108) or optical thickness of an optically smoothed test object (122), wherein the interferometer (10) is configured to simultaneously illuminate the optically smoothed test object with multiple object waves (14.1, 14.2, 14.3) having different wavelengths from each other, and to superimpose the object waves (14.1, 14.2, 14.3) deformed by the illuminated test object onto a coherent reference wave on an image capturing device (K), and to decompose the spectrum of the superimposed interferogram into wavelength-specific partial interferograms.

The application relates to a chromatic aberration compensation method in dual-wavelength digital holography, which comprises the following steps: obtaining a dual-wavelength interference pattern containing two wavelengths simultaneously; calculating the complex amplitudes of the two wavelengths at the camera plane; performing numerical propagation of the object wavefronts of the two wavelengths in a set defocus range by using an angular spectrum propagation algorithm to obtain the complex amplitudes of the two wavelengths at different axial positions in the defocus range; calculating the corresponding single-wavelength phase distributions in the defocus range; calculating the dual-wavelength synthetic phase distribution under all combinations of the two wavelengths at different axial positions; obtaining the gradient value of the dual-wavelength synthetic phase distribution when the two wavelengths are at different axial propagation positions; and subtracting the two single-wavelength phases according to the minimum position of the gradient value of the dual-wavelength synthetic phase distribution to obtain the chromatic aberration compensated dual-wavelength synthetic phase. The chromatic aberration compensation method in dual-wavelength digital holography can greatly improve the phase measurement accuracy.

Device for determining distance, with at least one light source for generating bichromatic light waves (E1, E2) with a first and second frequency (ω1, ω2), with a device for generating bichromatic reference waves (E Lo1 , E Lo2 ), which is designed in such a way that, starting from the bichromatic light waves (E1, E2), bichromatic reference waves (E Lo1 , E Lo2 ) shifted by a difference frequency (A C0M2 ) are generated with a first and second reference frequency (ω'1, ω'2), where the bichromatic light waves illuminate a scene or an object and are referred to as object waves (E Obj,1,2 ) be reflected upon, with a demodulator that uses the difference frequency (Δω M2 ) is operated, wherein the distance determination device is designed such that the demodulator is completely free from the object waves (E) on its receiving range. Obj,1,2) is illuminated, while the bichromatic reference wave (E Lo1 , E Lo2 ) only illuminate a first reception area of ​​the demodulator, wherein a second reception area is based on a monochromatic reference wave (E Lo1 ) is illuminated with a first frequency (ω'1), with an evaluation device designed in such a way that a distance is determined based on signals demodulated in the first and second reception range of the demodulator.

Device for detecting the amplitude and phase of a wave field, with a light source for emitting a coherent plane light wave with a first frequency (ω1), with an oscillator to generate a modulation frequency (Δω), with an optical modulator to generate a reference light wave (E LO , ω1'), with a PMD sensor with multiple PMD pixels, each having a first and second integration node (A, B), wherein the PMD sensor and the optical modulator are operated with the modulation frequency (Δω) generated by the oscillator, wherein part of the light emitted by the light source is directed onto the optical modulator and the optical modulator shifts the first frequency (ω1) of the incoming light by the modulation frequency (Δω) so that a reference light wave (E) is present at the output of the optical modulator. LO) with a second frequency (ω1') is available, where a scene or object is illuminated with the first coherent plane light wave and the light wave reflected by the object is an object light wave (E Obj ) forms, where the PMD sensor is connected to the object light wave (E Obj ) and the reference light wave (E LO ) is illuminated in such a way that the angles of incidence or the directions of propagation of both waves are aligned at a predetermined angle (α) to each other and both waves interfere, where the interference is time-varying and has a period corresponding to the frequency shift (Δω) or the modulation frequency (Δω), where the interference is captured alternately by the first and second integration nodes (A,B) in phase synchrony with the modulation frequency (Δω), where, after an integration time for a PMD pixel, a difference signal (AB) is available, from a lateral distribution of the difference signals and taking into account the angles of incidence of the object and reference waves, a laterally resolved amplitude and a laterally resolved phase of the object wave can be determined.