A holographic antenna comprises an optically transparent substrate; a hologram arranged on a first surface of the substrate, the hologram comprising two or more hologram stripes, each having a plurality of linearly arranged hologram pixels, each comprising a switching component; a ground plane arranged on a second surface, opposite the first surface, of the substrate; one or more surface wave launchers arranged on or in a surface of the substrate, the one or more surface wave launchers being configured to feed a feeding signal in a frequency range above 50 GHz into the hologram; and control lines connected to the switching components of the hologram pixels for controlling the hologram pixels individually or in groups.

The invention relates to a method for detecting a measured value (dϕ/dx, M). According to the invention, provision is made for a sinusoidal excitation signal (Ue) with a predetermined excitation frequency (f), with or without a superposed DC component (Uoffset), to be fed to an input of a component (100, C), for at least one electron holography measuring step to be carried out, in which an electron beam (Se) is directed on the component (100, C), said electron-beam penetrating and/or passing the component (100, C) and subsequently being superposed with a reference electron-beam (Sr), and for an electrical hologram (EHG) arising by interference of the two electron beams (Se, Sr) during a predetermined measurement window (F) to be measured and the phase image (PB) to be ascertained therefrom, and for the measured value (M) to be formed on the basis of the phase image (PB), wherein the temporal length (Tf) of the measurement window (F) of the electron holography measuring step is shorter than half the period (T) of the sinusoidal excitation signal (Uc).

Subject positioning systems and methods are provided. A method may include obtaining first information of at least part of a subject when the subject is located at a preset position, and determining, based on the first information, a first position of each of one or more feature points located on the at least part of the subject. The method may include obtaining, using an imaging device, second information of the at least part of the subject when the subject is located at a candidate position. The method may further include determining, based on the second information, a second position of each of the one or more feature points, a first distance between the first position and the second position for each feature point of the one or more feature points, and a target position of the subject based at least in part on the one or more first distances.

A holography sensor system is provided that includes an illuminator, a backscatter array, an array controller, and processing circuitry. The illuminator may be configured to output an illumination signal into a target volume. The backscatter array may comprise a plurality of backscatter elements. The array controller operably coupled to the backscatter elements, and the array controller may be configured to activate selected backscatter elements to enable the selected backscatter elements to transmit a backscatter signal in response to receipt of the illumination signal. The receiver may be configured to receive the backscatter signals from the selected backscatter elements. The processing circuitry may be configured to receive the backscatter data based on the backscatter signals from the receiver, aggregate the backscatter data with other backscatter data to form a holographic field measurement data set, and generate an image of the target volume based on the holographic field measurement data set.

An apparatus and method to produce a hologram of an object includes an electromagnetic radiation assembly configured to receive a received electromagnetic radiation, such as light, from the object. The electromagnetic radiation assembly is further configured to diffract the received electromagnetic radiation and transmit a diffracted electromagnetic radiation. An image capture assembly is configured to capture an image of the diffracted electromagnetic radiation and produce the hologram of the object from the captured image.

An apparatus and method to produce a hologram of an object includes an electromagnetic radiation assembly configured to receive a received electromagnetic radiation, such as light, from the object. The electromagnetic radiation assembly is further configured to diffract the received electromagnetic radiation and transmit a diffracted electromagnetic radiation. An image capture assembly is configured to capture an image of the diffracted electromagnetic radiation and produce the hologram of the object from the captured image.

Apparatuses and methods for improved reconstructions of electron-based holograms are disclosed herein. An example method at least includes forming a hologram of a sample and a known object, forming a reconstruction of the known object using a reconstruction algorithm, comparing the reconstruction of the known object to a reference reconstruction of the known object, and adjusting the reconstruction algorithm based on the comparison of the reconstruction of the known object to the reference reconstruction of the known object. The example method may further include forming a reconstruction of the sample using the adjusted reconstruction algorithm.

A computer calculates interference fringe phase estimated value data (30) of a phase-restored object image by performing iterative approximation calculation using interference fringe intensity data (10) measured by a digital holography apparatus and interference fringe phase initial value data (20), which is an estimated initial phase value of the image of the object. The interference fringe phase initial value data (20) is calculated by an initial phase estimator (300). The initial phase estimator (300) is constructed by implementing machine learning using interference fringe intensity data and the like for learning. The computer acquires reconfigured intensity data (40) and reconfigured phase data (50) by performing optical wave propagation calculation using the interference fringe phase estimation value data (30) of the image of the object acquired through phase restoration, and the interference fringe intensity data (10) used as input data for the initial phase estimator (300). This provides an iterative approximation calculation method and the like capable of making an initial value of a solution used in the iterative approximation calculation method a value close to the true value.

Apparatuses and methods for comparative holographic imaging to improve structural and molecular information of reconstructions is disclosed herein. An example method at least includes acquiring a plurality of holograms of a sample, wherein each hologram of the plurality of holograms is acquired at a different electron beam energy, and determining atomic and structural information of the sample based at least on a comparison of at least two of the holograms of the plurality of holograms.

Methods for using electron diffraction holography to investigate a sample, according to the present disclosure include the initial steps of emitting a plurality of electrons toward the sample, forming the plurality of electrons into a first electron beam and a second electron beam, and modifying the focal properties of at least one of the two beams such that the two beams have different focal planes. Once the two beams have different focal planes, the methods include focusing the first electron beam such that it has a focal plane at or near the sample, and focusing the second electron beam so that it is incident on the sample, and has a focal plane in the diffraction plane. An interference pattern of the first electron beam and the diffracted second electron beam is then detected in the diffraction plane, and then used to generate a diffraction holograph.