Abstract
SuperSpec is a compact on-chip spectrometer operating at mm and sub-mm wavelengths which will enable the construction of sensitive multibeam spectrometers. SuperSpec employs a filter bank architecture, consisting of lithographically patterned niobium superconducting microstrip mm-wave resonators. The power admitted by each resonator is detected by a titanium nitride lumped-element kinetic inductance detector (KID) with resonant frequency from 100 to 200 MHz. We present a characterization of the detector noise performance down to 10 mK measured in a dark setting. We report a device NEP of 2.7×10-18WHz-1/2 at 210 mK, which is below the expected photon noise level at high-altitude ground-based observatories. The NEP decreases to a constant value of approximately 7.0×10-19WHz-1/2 below 130 mK. The white noise is well modeled by thermal generation–recombination noise (GR noise) down to 130 mK and a noise floor at low temperatures. Moreover, the addition of low-pass coaxial filters further reduces the noise floor to achieve an NEP of 5.7×10-19WHz-1/2 below 100 mK. We discuss a photolithographic technique to adjust KID resonances that results in an f0 designed versus measured scatter of 1.7 × 10 - 5, which will allow a significant reduction in resonators lost to clashes in full-scale designs. Finally, we present a demonstration of a new ROACH-2-based readout system operating below 500 MHz and show preliminary data indicating the suitability of this system for future highly multiplexed KID arrays.
Original language | English (US) |
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Pages (from-to) | 1024-1032 |
Number of pages | 9 |
Journal | Journal of Low Temperature Physics |
Volume | 193 |
Issue number | 5-6 |
DOIs | |
State | Published - Dec 1 2018 |
Keywords
- Kinetic inductance detector
- NEP
- ROACH-2
- Spectrometer
- SuperSpec
- TiN
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- General Materials Science
- Condensed Matter Physics