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In order for telescopes to obtain good and precise images they need to see through atmospheric turbulence. To accomplish this and compensate for atmospheric turbulence we use Adaptive Optics technologies. In this thesis we analyze the…

Instrumentation and Methods for Astrophysics · Physics 2023-10-13 Cesar Laguna

Context: A turbulent atmosphere causes atmospheric piston variations leading to rapid changes in the optical path difference of an interferometer, which causes correlated flux losses. This leads to decreased sensitivity and accuracy in the…

Instrumentation and Methods for Astrophysics · Physics 2014-09-05 A. Müller , J. -U. Pott , A. Mérand , R. Abuter , F. Delplancke-Ströbele , Th. Henning , R. Köhler , Ch. Leinert , S. Morel , T. Phan Duc , E. Pozna , A. Ramirez , J. Sahlmann , C. Schmid

Today, wide-open, high-resolution Doppler frequency shift (DFS) estimation is essential for radar, microwave/millimeter-wave, and communication systems. Using photonics technology, an effective approach is proposed and experimentally…

Optics · Physics 2014-04-09 Xihua Zou , Wangzhe Li , Bing Lu , Wei Pan , Lianshan Yan , Liyang Shao

We present broadband group velocity dispersion (GVD) measurements of commercially available ultra-high numerical aperture fibers (UHNA1, UHNA3, UHNA4, UHNA7 and PM2000D from Coherent-Nufern). Although these fibers are attractive for…

Instrumentation and Detectors · Physics 2018-07-04 Piotr Ciąćka , Anupamaa Rampur , Alexander Heidt , Thomas Feurer , Mariusz Klimczak

We present a filtering technique that can be applied to individual baselines of wide-bandwidth, wide-field interferometric data to geometrically select regions on the celestial sphere that contain primary calibration sources. The technique…

Instrumentation and Methods for Astrophysics · Physics 2015-05-13 Aaron R. Parsons , Donald C. Backer

We present an elegant application of matterwave interferometry to the velocimetry of cold atoms whereby, in analogy to Fourier transform spectroscopy, the 1-D velocity distribution is manifest in the frequency domain of the interferometer…

Atomic Physics · Physics 2019-03-06 Max Carey , Jack Saywell , David Elcock , Mohammad Belal , Tim Freegarde

Context: Dynamical studies of irradiated circumstellar disks require an accurate treatment of radiation transport to, for example, properly determine cooling and fragmentation properties. The radiation transport algorithm should be as fast…

Solar and Stellar Astrophysics · Physics 2013-06-20 Rolf Kuiper , Ralf S. Klessen

Interferometry techniques are essential for extracting phase information from optical systems, enabling precise measurements of dispersion and highly sensitive detection of perturbations. While phase sensing offers enhanced sensitivity…

The study of the continuum radiative transfer problem inside circumstellar envelopes is both a theoretical and numerical challenge, especially in the frequency-dependent and multi-dimensional case. While approximate methods are easier to…

Solar and Stellar Astrophysics · Physics 2024-10-14 J. Perdigon , M. Faurobert , G. Niccolini

Aims: The effect of frequency-dependent AGN core positions (``core-shifts'') on radio Very Long Baseline Interferometry (VLBI) global astrometry measurements is investigated. Methods: The basic equations relating to VLBI astrometry are…

Instrumentation and Methods for Astrophysics · Physics 2015-05-14 R. W. Porcas

For further gravitational wave (GW) detections, it is significant to invent a technique to reduce all kinds of mirror displacement noise dominant at low frequencies for ground-based detectors. The neutron displacement-noise-free…

Time delay interferometry (TDI) is a post-processing technique used in the Laser Interferometer Space Antenna (LISA) to reduce laser frequency noise by building an equal-arm interferometer via combining time-shifted raw phase measurements.…

General Relativity and Quantum Cosmology · Physics 2022-04-06 Olaf Hartwig , Martina Muratore

The displacement- and frequency-noise-free interferometer (DFI) is a multiple laser interferometer array for gravitational wave detection free from both the displacement noise of optics and laser frequency noise. So far, partial…

General Relativity and Quantum Cosmology · Physics 2009-10-29 K. Kokeyama , S. Sato , A. Nishizawa , S. Kawamura , Y. Chen , A. Sugamoto

Difference-frequency generation (DFG) is a powerful technique for generating widely tunable infrared radiation. However, conventional phase-matching schemes may require tuning multiple parameters-such as the wavelengths, crystal…

An interferometer design that cancels all displacement noises of its test masses and maintains a gravitational-wave (GW) signal by combining multiple detector signals is called a displacement noise-free interferometer (DFI). The idea has…

We present a single-source dual atom interferometer and utilize it as a gradiometer for precise gravitational measurements. The macroscopic separation between interfering atomic wave packets (as large as 16 cm) reveals the interplay of…

We investigate experimentally a cascade of temperature-compensated unequal-path interferometers that can be used to measure frequency states in a high-dimensional quantum distribution system. In particular, we demonstrate that…

Quantum Physics · Physics 2017-04-26 Nurul T. Islam , Andres Aragoneses , A. Lezama , Jungsang Kim , Daniel J. Gauthier

Developments in the stability of modern spectrographs have led to extremely precise instrumental radial velocity (RV) measurements. For most stars, the detection limit of planetary companions with these instruments is expected to be…

Earth and Planetary Astrophysics · Physics 2023-06-28 Quang H. Tran , Megan Bedell , Daniel Foreman-Mackey , Rodrigo Luger

Time-Delay Interferometry (TDI) is essential for space-based gravitational wave (GW) missions, as it suppresses laser frequency noise and achieve the required sensitivity. Beyond the standard Michelson configuration, a variety of…

General Relativity and Quantum Cosmology · Physics 2025-08-05 Gang Wang

Radio Frequency Identification (RFID) is a widely used technology for identifying and locating objects equipped with low-cost RFID transponders (tags). UHF (Ultra High Frequency) RFID operates in frequency bands around 900 MHz and supports…

Signal Processing · Electrical Eng. & Systems 2025-11-26 Clemens Korn , Joerg Robert
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