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X-Spec is a moderate-resolution (R=400–700), multi-beam survey spectrometer covering the 190–520 GHz band under development for CCAT. It will employ a superconducting lithographically-patterned on-chip spectrometer technology, called SuperSpec. The spectrometer employs a filterbank architecture, and consists of a series of half-wave resonators formed by lithographically-patterned superconducting transmission...
Fabry-Perot resonances in planar terahertz metamaterial structures have been investigated both theoretically and experimentally. It has been demonstrated that performance of frequency-agile metamaterial modulator can be optimized by adjustment of dielectric substrate thickness in accordance with operating frequency of metamaterial.
X-Spec is a multi-beam, R=400–700 survey spectrometer covering 190–520 GHz under development for CCAT. It measure the bright atomic fine-structure and molecular rotational transitions that cool galaxies' interstellar gas, in particular, the 158 μm rest-frame [CII] transition which is accessible from z=9.5 to z=3.5, With the wide bandwidth and multi-object capability, X-Spec/CCAT will be more powerful...
Coherent detection of very weak THz signals is important in astronomy, spectroscopy, and communications. We report on coherent up-conversion of THz radiation into the optical telecommunication range. All resonant phase-matched conversion can be achieved in a whispering gallery mode (WGM) resonator. Furthermore we present first results on WGM resonators that can be coupled to both THz radiation as...
We designed, fabricated and characterized a tunable metamaterial in the terahertz frequency range based on a hybrid topology composed of metallic cut-wires separated by vanadium dioxide (VO2) patterns. The response of the hybrid metamaterial is significantly changing as the VO2 material is performing a reversible thermally or electrically-driven metal-insulator transition which drastically modifies...
We present measurements from a prototype array of superconducting kinetic inductance detectors optimized for 150 GHz radiation and commercially fabricated from 20 nm aluminum films on silicon wafers.
We demonstrate a design of terahertz metamaterial bandstop filter, which is based on arrays of split-ring resonators (SRRs) and pair rods of vanadium dioxide (VO2). Each unit cell comprises a pair of SRRs with their splits in opposite directions and a pair of VO2 rods crossing the SRR perpendicular to the split directions. Two stopband electromagnetic resonances can be switched by optical-pumping...
THE upcoming nuclear fusion plants, such as ITER, pose new challenges under many scientific and technological fields. The requirements of the materials suitable for the operations in such facilities often involve optical, thermal and mechanical characteristics. It's the case of the diamond windows, whose outstanding performances make them the ideal choice as vacuum and tritium barriers inside the...
A broadband terahertz reflective linear polarization convertor is proposed. The structure is composed of a metallic disk and split-ring resonators in proximity to a ground plane. It is found that the structure exhibits three neighboring resonances, from which the linear polarization of incident light can be rotated to its orthogonal counterpart after reflection. Both simulated and experimental results...
Whispering gallery mode (WGM) resonators have high Q factors and small modal volumes and can thus show strong non-linear interactions. Most of the interesting non-linear materials are crystalline and feature high refractive indices such that efficient coupling to the resonator is challenging. We present a study on high refractive index WGM resonators and show that coupling via a crystalline dielectric...
We recently demonstrated ultrathin, broadband, and highly efficient (reaching 88%) terahertz (THz) metamaterial structures exhibiting near-perfect anomalous (or generalized laws of) refraction. These structures redirect up to 61% of the incident power into the anomalous beam and practically eliminate the ordinary component. Here exploit this breakthrough to create more complex optical elements, specifically...
Microwave kinetic inductance detectors (MKIDs) promise high sensitivity, combined with device simplicity and intrinsic multiplexibility. We have measured the response and noise equivalent power (NEP) of an all-aluminium, antenna coupled MKID at 1.54 THz, both as a function of radiation power and as a function of readout power. Eight optical filters and a box-in-box configuration at the bath temperature,...
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