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Differential wavefront sensing is an essential technique for optimising the performance of many precision interferometric experiments. Perhaps the most extensive application of this is for alignment sensing using radio-frequency beats…

Instrumentation and Detectors · Physics 2021-05-26 Daniel D. Brown , Huy Tuong Cao , Alexei Ciobanu , Peter Veitch , David Ottaway

Modern cameras with large apertures often suffer from a shallow depth of field, resulting in blurry images of objects outside the focal plane. This limitation is particularly problematic for fixed-focus cameras, such as those used in smart…

Computer Vision and Pattern Recognition · Computer Science 2025-10-28 Xinge Yang , Chuong Nguyen , Wenbin Wang , Kaizhang Kang , Wolfgang Heidrich , Xiaoxing Li

Optical interference is not only a fundamental phenomenon that has enabled new theories of light to be derived but it has also been used in interferometry for the measurement of small displacements, refractive index changes and surface…

Optics · Physics 2021-10-28 Chen Yang , Zhi-Yuan Zhou , Yan Li , Shi-Kai Liu , Zheng Ge , Guang-Can Guo , Bao-Sen Shi

We have developed a new on-axis digital holographic technique, heterodyne holography. The resolution of this technique is limited mainly by the amount of data recorded on two-dimensional photodetectors, i.e., the number of pixels and their…

Optics · Physics 2011-12-26 Frédérique Le Clerc , Michel Gross , Laurent Collot

Phase imaging techniques extract the optical path-length information of a scene, whereas wavefront sensors provide the shape of an optical wavefront. Since these two applications have different technical requirements, they have developed…

Optics · Physics 2018-02-28 F. Soldevila , V. Durán , P. Clemente , J. Lancis , E. Tajahuerce

Microscopes and various forms of interferometers have been used for decades in optical metrology of objects that are typically larger than the wavelength of light {\lambda}. However, metrology of subwavelength objects was deemed impossible…

Dynamic thin film interferometry is a technique used to non-invasively characterize the thickness of thin liquid films. Recovering the underlying thickness from the captured interferograms, unconditionally and automatically is still an open…

Holography is an established technique for measuring the wavefront of optical signals through interferometric combination with a reference wave. Conventionally the integration time of a hologram is limited by the interferometer coherence…

Optics · Physics 2023-12-13 Guillaume Thekkadath , Duncan England , Benjamin Sussman

Interferometric Synthetic Aperture Radar (InSAR) Imaging methods are usually based on algorithms of match-filtering type, without considering the scene's characteristic, which causes limited imaging quality. Besides, post-processing steps…

Signal Processing · Electrical Eng. & Systems 2022-10-07 Xu Zhan , Xiaoling Zhang , Shunjun Wei , Jun Shi

A method to create instructive, nonuniform aperture functions using spatial frequency filtering is described. The diffraction from a single slit in the Fresnel limit and the interference from a double slit in the Fraunhofer limit are…

Optics · Physics 2015-06-05 Lowell T. Wood

In this letter, we study a nonlinear interferometric setup based on diffraction rather than beam combining. It consists of a nonlinear analogue of Young's double-slit experiment where a nonlinear material is placed exactly after one of the…

Optics · Physics 2023-07-19 Vassilis Paltoglou , Nikolaos K. Efremidis

This paper presents an architecture for Ultrasound Beamforming using Synthetic Transmit Aperture with Low Complexity and High SNR for medical imaging. Synthetic Transmit Aperture is a novel approach in ultrasound imaging system by which…

Signal Processing · Electrical Eng. & Systems 2024-07-16 Thenmozhi Elango , Samiyuktha Kalalii , P Rajalakshmi

The interaction of light with objects and media moving at relativistic and superluminal speeds enables unconventional phenomena such as Fresnel drag, Hawking radiation, and light amplification. Synthetic motion, facilitated by modulated…

In this paper we present an experimental setup based on Laser Optical Feedback Imaging (LOFI) and on Synthetic Aperture (SA) with translational scanning by galvanometric mirrors for the purpose of making deep and resolved images through…

This paper presents the results of a Fresnel Interferometric Array testbed. This new concept of imager involves diffraction focussing by a thin foil, in which many thousands of punched subapertures form a pattern related to a Fresnel zone…

Astrophysics · Physics 2008-08-07 Denis Serre , Laurent Koechlin , Paul Deba

Optical imaging through complex scattering media is one of the major technical challenges with important applications in many research fields, ranging from biomedical imaging, astronomical telescopy, and spatially multiplex optical…

Conventional ground-based astronomical observations suffer from image distortion due to atmospheric turbulence. This can be minimized by choosing suitable geographic locations or adaptive optical techniques, and avoided altogether by using…

Instrumentation and Methods for Astrophysics · Physics 2016-03-04 Peng Kian Tan , Aik Hui Chan , Christian Kurtsiefer

In this article, we report an imaging method, termed Fourier ptychographic microscopy (FPM), which iteratively stitches together a number of variably illuminated, low-resolution intensity images in Fourier space to produce a wide-field,…

Optics · Physics 2014-05-02 Guoan Zheng , Roarke Horstmeyer , Changhuei Yang

Scattering scanning near-field optical microscopy enables optical imaging and characterization of plasmonic devices with nanometer-scale resolution well below the diffraction limit. This technique enables developers to probe and understand…

The maximum baseline, and therefore resolution, of optical astronomical interferometers is limited by attenuation and phase noise within the optical path between the apertures and beam combiner, as well as the practical challenges of…