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The redshifted 21 cm brightness distribution from neutral hydrogen is a promising probe into the cosmic dark ages, cosmic dawn, and re-ionization. LOFAR's Low Band Antennas (LBA) may be used in the frequency range 45 MHz to 85 MHz (30>z>16)…

Instrumentation and Methods for Astrophysics · Physics 2015-06-16 H. K. Vedantham , L. V. E. Koopmans , A. G. de Bruyn , S. J. Wijnholds , B. Ciardi , M. A. Brentjens

The development of optical fibers has revolutionized telecommunications by enabling long-distance broad-band transmission with minimal loss. In turn, the ubiquity of high-quality low-cost fibers enabled a number of additional applications,…

Optics · Physics 2017-03-30 Brandon Redding , Mansoor Alam , Martin Seifert , Hui Cao

We designed a high-resolution compact spectrometer based on an evanescently-coupled multimode spiral waveguide. Interference between the modes in the waveguide forms a wavelength-dependent speckle pattern which is used as a fingerprint to…

Instrumentation and Detectors · Physics 2016-08-26 Brandon Redding , Seng Fatt Liew , Yaron Bromberg , Raktim Sarma , Hui Cao

Coherent multistatic radio imaging represents a pivotal opportunity for forthcoming wireless networks, which involves distributed nodes cooperating to achieve accurate sensing resolution and robustness. This paper delves into cooperative…

Frequency metrology lies at the heart of precision measurement. Optical frequency combs provide a coherent link uniting the microwave and optical domains in the electromagnetic spectrum, with profound implications in timekeeping, sensing…

Phase-sensitive coherent imaging exploits changes in the phases of backscattered light to observe tiny alterations of scattering structures or variations of the refractive index. But moving scatterers or a fluctuating refractive index…

In this paper, we present theoretical details and the underlying architecture of a hybrid optoelectronic correlator that correlates images using Spatial Light Modulators (SLM), detector arrays and Field Programmable Gate Array (FPGA). The…

In this paper, we describe the principle of a multi-aperture interferometer that uses a phase-shifting technique and is suitable for quick, snapshot imaging of astrophysical objects at extreme angular resolution through Fourier inversion. A…

Optics · Physics 2015-05-28 Francois Henault

Quantum spectroscopy was performed using the frequency-entangled broadband photon pairs generated by spontaneous parametric down-conversion. An absorptive sample was placed in front of the idler photon detector, and the frequency of signal…

Quantum Physics · Physics 2009-11-10 Atsushi Yabushita , Takayoshi Kobayashi

A laser frequency combs is a broad spectrum composed of equidistant narrow lines. Initially invented for frequency metrology, such combs enable new approaches to spectroscopy over broad spectral bandwidths, of particular relevance to…

Optics · Physics 2019-03-01 Nathalie Picqué , Theodor W. Hänsch

A correlation optical time-domain reflectometry (COTDR) method is presented, which measures the propagation delay with an accuracy of a few picoseconds. This accuracy is achieved using a test signal data rate of 10 Gbit/s and employing…

Optics · Physics 2022-02-24 Florian Azendorf , Annika Dochhan , Michael H. Eiselt

Optical parametric down-conversion is a common source for the generation of non-classical correlated photonic states. Using a parametric down-conversion source and photon-number resolving detectors, we measure the two-mode photon-number…

Quantum Physics · Physics 2014-02-04 L. Dovrat , M. Bakstein , D. Istrati , E. Megidish , A. Halevy , H. S. Eisenberg

The uplink where both the transmitter and receiver can use a large antenna array is considered. This is proposed as a method of antenna offloading and connecting small cell access points (SCAP) in a Two-Tier cellular network. Due to having…

Information Theory · Computer Science 2016-05-27 Namal Rajatheva , Elvino Sousa

Speckle patterns are inherent features of coherent light propagation through complex media. As a result of interference, they are sensitive to multiple experimental parameters such as the configuration of disorder or the propagating…

Dual-comb interferometry is a measurement technique that uses two laser frequency combs to retrieve complex spectra in a line-by-line basis. This technique can be implemented with electro-optic frequency combs, offering intrinsic mutual…

Optics · Physics 2016-09-21 Vicente Duran , Peter A. Andrekson , Victor Torres-Company

A wideband analog correlator has been constructed for the Yuan-Tseh Lee Array for Microwave Background Anisotropy. Lag correlators using analog multipliers provide large bandwidth and moderate frequency resolution. Broadband IF…

Doppler orbitography uses the Doppler shift in a transmitted signal to determine the orbital parameters of satellites including range and range-rate (or radial velocity). We describe two techniques for atmospheric-limited optical Doppler…

Instrumentation and Methods for Astrophysics · Physics 2020-06-09 Benjamin P. Dix-Matthews , Sascha W. Schediwy , David R. Gozzard , Simon Driver , Karl Ulrich Schreibe , Randall Carman , Michael Tobar

It is widely believed that range resolution, the ability to distinguish between two closely situated targets, depends inversely on the bandwidth of the transmitted radar signal. Here we demonstrate a different type of ranging system, which…

Signal Processing · Electrical Eng. & Systems 2021-06-30 Rony Komissarov , Vitali Kozlov , Dmitry Filonov , Pavel Ginzburg

We introduce the first method to enable an optical amplification of a coherent Raman spectroscopy signal called radio frequency Doppler Raman spectroscopy. Doppler Raman measurements amplify the optical signals in coherent Raman…

Synchronization of transceiver chains is a major challenge in the practical realization of massive MIMO and especially distributed massive MIMO. While frequency synchronization is comparatively easy to achieve, estimating the carrier phase…

Signal Processing · Electrical Eng. & Systems 2022-12-23 Florian Euchner , Phillip Stephan , Marc Gauger , Stephan ten Brink
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