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Technological advances in the fabrication of nanophotonic circuits have driven the scientific community to increasingly focus on the precise tailoring of their key optical properties, over a broadband spectral domain. In this context, the…

We present our results for simultaneous measurement of the refractive indices of gallium arsenide (GaAs) and aluminum gallium arsenide (Al$_\mathrm{x}$Ga$_\mathrm{1-x}$As) from $2.0$ to $7.1\,\mathrm{\mu m}$ ($5000$ to…

A 2.5 degree field diameter corrector lens design for the Cassegrain focus of the VISTA 4 meter telescope is presented. It comprises four single elements of glasses with high UV transmission, all axi-symmetric for operation at the zenith.…

Instrumentation and Methods for Astrophysics · Physics 2015-06-22 Peter Gillingham , Will Saunders

We present a graphical interface designed to demonstrate the techniques of radio interferometry used by telescopes like ALMA, e-Merlin, the JVLA and SKA, in a manner accessible to the general public. Interferometry is an observational tech-…

Instrumentation and Methods for Astrophysics · Physics 2012-11-02 Adam Avison , Samuel J George

We theoretically investigate the design of thin subwavelength gratings possessing high-reflectivity and high-$Q$ resonances when illuminated at normal incidence by a Gaussian beam. We compare the performances of single-period and…

Optics · Physics 2025-08-12 Gurpreet Singh , Trishala Mitra , Søren P. Madsen , Aurélien Dantan

In this work, we present the design and manufacturing of the two multi-mode antenna arrays of the COSMO experiment and the preliminary beam pattern measurements of their fundamental mode compared with simulations. COSMO is a cryogenic…

Modern imaging and sensing in complex environments, ranging from biomedical diagnostics to wireless communication, relies on accurately measuring and then controlling the wave propagation. Conventional approaches demand large arrays of…

We characterize a near-infrared C-RED ONE camera from First Light Imaging (FLI). This camera uses a SAPHIRA electron avalanche photo-diode array (e-APD) from Leonardo (previously Selex). To do so, we developed a model of the signal…

Instrumentation and Methods for Astrophysics · Physics 2018-07-27 Cyprien Lanthermann , Jean-Baptiste Le Bouquin , Narsireddy Anugu , John D. Monnier , Stefan Kraus

In this paper, a single layer Coplanar Waveguide-fed microstrip patch antenna array is presented for biomedical applications. The proposed antenna array is realized on a transparent and flexible Polyethylene Terephthalate substrate, has 1x4…

Medical Physics · Physics 2019-06-26 U. Farooq , A. Iftikhar , M. S. Khan , M. F. Shafique , Raed M. Shubair

As opposed to metasurfaces, metagratings represent themselves sparse arrangements of scatterers. Established rigorous analytical models allow metagratings to overcome performance of metasurfaces in beam steering applications while handling…

Applied Physics · Physics 2020-04-22 Vladislav Popov , Fabrice Boust , Shah Nawaz Burokur

We present results from a first attempt to mitigate radio frequency interference in real-time during astronomical measurements with a phased array feed on the 64 m Parkes radio telescope. Suppression of up to 20 dB was achieved despite…

Instrumentation and Methods for Astrophysics · Physics 2017-10-16 A. P. Chippendale , G. Hellbourg

We propose an uplink massive MIMO system using an array of holographic metasurfaces as a sector antenna. The antenna consists of a set of rectangular waveguide-fed metasurfaces combined along the elevation direction into a planar aperture,…

Signal Processing · Electrical Eng. & Systems 2021-08-31 Insang Yoo , David R. Smith

CUBES is the Cassegrain U-Band Efficient Spectrograph, a high-efficiency instrument operating in the UV spectral range between 300nm and 400nm with a resolution not less than 20000. CUBES is to be installed at a Cassegrain focus of the Very…

Instrumentation and Methods for Astrophysics · Physics 2022-03-30 U. D. Zeitner , H. Dekker , F. Burmeister , T. Flügel-Paul , A. Bianco , A. Zanutta

With 30 antennas and a maximum baseline length of 25 km, the Giant Metrewave Radio Telescope (GMRT) is the premier low-frequency radio interferometer today. We have carried out a study of possible expansions of the GMRT, via adding new…

We study theoretically the accuracy of the method based on the Fourier property of lenses that is commonly used for the far field measurement. We consider a simple optical setup in which the far-field intensity pattern of a light beam…

Optics · Physics 2013-07-19 Pierre Suret , Stephane Randoux

This paper presents the design and characterization of a rectangular microstrip patch antenna array optimized for operation within the Ku-band frequency range. The antenna array is impedance-matched to 50 Ohms and utilizes a microstrip line…

Systems and Control · Electrical Eng. & Systems 2024-05-29 Muhammad Asfar Saeed , Augustine O. Nwajana

In conventional colocated multiple-input multiple-output (MIMO) radars, practical waveform constraints including peak-to-average power ratio, constant or bounded modulus lead to a significant performance reduction of transmit beampattern,…

Signal Processing · Electrical Eng. & Systems 2024-10-08 Shengyao Chen , Minghui He , Longyao Ran , Hongtao Li , Feng Xi , Sirui Tian , Zhong Liu

We demonstrate a wide-band diplexed focal plane suitable for observing low-frequency foregrounds that are important for cosmic microwave background polarimetry. The antenna elements are composed of slotted bowtie antennas with 60% bandwidth…

Modelling complex line emission in the interstellar medium (ISM) is a degenerate, high-dimensional problem. Here, we present McFine, a tool for automated multi-component fitting of emission lines with complex hyperfine structure, in a fully…

Astrophysics of Galaxies · Physics 2024-09-11 Thomas G. Williams , Elizabeth J. Watkins

Astronomers usually need the highest angular resolution possible, but the blurring effect of diffraction imposes a fundamental limit on the image quality from any single telescope. Interferometry allows light collected at widely-separated…

Instrumentation and Methods for Astrophysics · Physics 2015-05-20 John D. Monnier , Ronald J. Allen