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A combination of spatial interference patterns and spectral interferometry are used to find the global phase for non-collinear two-dimensional Fourier-transform (2DFT) spectra. Results are compared with those using the spectrally resolved…

Optics · Physics 2011-12-13 Alan D. Bristow , Denis Karaiskaj , Xingcan Dai , Steven T. Cundiff

Temporal focusing two-photon microscopy enables high resolution imaging of fine structures in vivo over a large volume. A limitation of temporal focusing is that signal-to-background ratio and resolution degrade rapidly with increasing…

In this paper we introduce a new 2D modulation technique called OTFS (Orthogonal Time Frequency & Space) that transforms information carried in the Delay-Doppler coordinate system to the familiar time-frequency domain utilized by…

Information Theory · Computer Science 2016-08-11 Anton Monk , Ronny Hadani , Michail Tsatsanis , Shlomo Rakib

Aberrations and multiple scattering in biological tissues critically distort light beams into highly complex speckle patterns. In this regard, digital optical phase conjugation (DOPC) is a promising technique enabling in-depth focusing.…

Orthogonal Time Frequency Space (OTFS) modulation exploits the sparsity of Delay-Doppler domain channels, making it highly effective in high-mobility scenarios. Its accurate channel estimation supports integrated sensing and communication…

Signal Processing · Electrical Eng. & Systems 2025-05-13 Guangyu Lei , Yanduo Qiao , Tianhao Liang , Weijie Yuan , Tingting Zhang

Doppler spectroscopy has uncovered or confirmed all the known planets orbiting nearby stars. Two main techniques are used to obtain precision Doppler measurements at optical wavelengths. The first approach is the gas cell method, which…

Earth and Planetary Astrophysics · Physics 2015-06-04 Guillem Anglada-Escudé , R. Paul Butler

Control of light through a microscope objective with a high numerical aperture is a common requirement in applications such as optogenetics, adaptive optics, or laser processing. Light propagation, including polarization effects, can be…

Optics · Physics 2023-03-22 Ivan Vishniakou , Johannes D. Seelig

The basic principle of astronomical interferometry is to derive the angular distribution of radiation in the sky from the Fourier transform of the electric field on the ground. What is so special about the Fourier transform? Nothing, it…

Instrumentation and Methods for Astrophysics · Physics 2015-01-30 Brian C. Lacki

Future large space telescopes will be equipped with adaptive optics (AO) to overcome wavefront aberrations and achieve high contrast for imaging faint astronomical objects, such as earth-like exoplanets and debris disks. In contrast to AO…

Instrumentation and Methods for Astrophysics · Physics 2020-01-07 He Sun , N. Jeremy Kasdin , Robert Vanderbei

Motivated by future automotive applications, we study the joint target detection and parameter estimation problem using orthogonal time frequency space (OTFS), a digital modulation format robust to time-frequency selective channels.…

Signal Processing · Electrical Eng. & Systems 2020-04-24 Lorenzo Gaudio , Mari Kobayashi , Giuseppe Caire , Giulio Colavolpe

A dual-excitation method for resonant-frequency tracking in scanning probe microscopy based on amplitude detection is developed. This method allows the cantilever to be operated at or near resonance for techniques where standard phase…

Materials Science · Physics 2008-03-13 B J Rodriguez , C Callahan , S V Kalinin , R Proksch

The technique of transmission spectroscopy -- the variation of the planetary radius with wavelength due to opacity sources in the planet's terminator region -- has been to date one of the most successful in the characterization of exoplanet…

Earth and Planetary Astrophysics · Physics 2021-10-04 Néstor Espinoza , Kathryn Jones

Optical imperfections, misalignments, aberrations, and even dust can significantly limit sensitivity in high-contrast imaging systems such as coronagraphs. An upstream deformable mirror (DM) in the pupil can be used to correct or compensate…

Instrumentation and Methods for Astrophysics · Physics 2015-06-15 Johanan L. Codona , Matthew Kenworthy

Dynamic graph signal processing provides a principled framework for analyzing time-varying data defined on irregular graph domains. However, existing joint time-vertex transforms such as the joint time-vertex fractional Fourier transform…

Signal Processing · Electrical Eng. & Systems 2025-11-21 Manjun Cui , Ziqi Yan , Yangfan He , Zhichao Zhang

We elaborate on the recently proposed orthogonal time frequency space (OTFS) modulation technique, which provides significant advantages over orthogonal frequency division multiplexing (OFDM) in Doppler channels. We first derive the…

Information Theory · Computer Science 2017-09-28 P. Raviteja , Khoa T. Phan , Qianyu Jin , Yi Hong , Emanuele Viterbo

Delay-Doppler alignment modulation (DDAM) is a novel technique to mitigate time-frequency doubly selective channels by leveraging the high spatial resolution offered by large antenna arrays and multi-path sparsity of millimeter wave…

Signal Processing · Electrical Eng. & Systems 2024-07-09 Xianda Liu , Zhiwen Zhou , Zhiqiang Xiao , Yong Zeng

Image subtraction in astronomy is a tool for transient object discovery and characterization, particularly useful in wide fields, and is well suited for moving or photometrically varying objects such as asteroids, extra-solar planets and…

Instrumentation and Methods for Astrophysics · Physics 2013-01-09 Steven Hartung

We propose a new Group Feature Selection method for Discriminative Correlation Filters (GFS-DCF) based visual object tracking. The key innovation of the proposed method is to perform group feature selection across both channel and spatial…

Computer Vision and Pattern Recognition · Computer Science 2019-08-05 Tianyang Xu , Zhen-Hua Feng , Xiao-Jun Wu , Josef Kittler

One of the major challenges of employing a dual-frequency phase-shifting algorithm for phase retrieval is its sensitivity to noise. Yun et. al [H Yun, B Li, S Zhang. 2017] proposed a dual-frequency method based on the Fourier transform…

Instrumentation and Detectors · Physics 2018-05-23 Minmin Wang , Canlin Zhou , Shuchun Si , Zhenkun Lei , Xiaolei Li , Hui Li , YanJie Li

We use JWST NIRCam short wavelength photometry to capture a transit lightcurve of the exoplanet HAT-P-14 b to assess performance as part of instrument commissioning. The short wavelength precision is 152 ppm per 27 second integration as…