Vic Haynes | Searcharxiv

arXiv2019

QUBIC: Exploring the primordial Universe with the Q\&U Bolometric Interferometer

In this paper we describe QUBIC, an experiment that will observe the polarized microwave sky with a novel approach, which combines the sensitivity of state-of-the art bolometric detectors with the systematic effects control typical of interferometers. QUBIC unique features are the so-called "self-calibration", a technique that allows us to clean the measured data from instrumental effects, and its spectral imaging power, i.e. the ability to separate the signal in various sub-bands within each frequency band. QUBIC will observe the sky in two main frequency bands: 150 GHz and 220 GHz. A technological demonstrator is currently under testing and will be deployed in Argentina during 2019, while the final instrument is expected to be installed during 2020.

astro-ph.IM↗

arXiv2014

Dog Bone Triplet Metamaterial Wave Plate

Metamaterials are artificially made sub-wavelength structures arranged in periodic arrays. They can be designed to interact with electromagnetic radiation in many different and interesting ways such as allowing radiation to experience a negative refractive index (NRI). We have used this technique to design and build a quasi-optical Half Wave Plate (HWP) that exhibits a large birefringence by virtue of having a positive refractive index in one axis and a NRI in the other. Previous implementations of such NRI-HWP have been narrow band ($\sim$1-3%) due to the inherent reliance on needing a resonance to create the NRI region. We manufacture a W-band prototype of a novel HWP that uses the Pancharatnam method to extend the bandwidth (up to more than twice) of a usual NRI-HWP. Our simulated and experimentally obtained results despite their differences show that a broadening of a flat region of the phase difference is possible even with the initially steep gradient for a single plate.

astro-ph.IM↗