Low-Frequency Noise Performance of Microstrip-Coupled Lumped-Element Aluminum KIDs using Hydrogenated Amorphous Silicon Parallel-Plate Capacitors for NEW-MUSIC

TL;DR

This study evaluates the low-frequency noise characteristics of aluminum kinetic inductance detectors with hydrogenated amorphous silicon capacitors, demonstrating their potential for photon-noise-limited performance in astronomical applications.

Contribution

It introduces a new detector design using a-Si:H PPCs for KIDs, showing they achieve photon-noise-limited performance at low frequencies relevant for astronomy.

Findings

Devices are GR noise dominated down to 0.1 Hz.

Under optical load, devices are likely dominated by GR and photon noise.

a-Si:H PPC-KIDs are viable for low modulation-rate applications.

Abstract

We present measurements of the low-frequency noise of microstrip-coupled, lumped-element aluminum kinetic inductance detectors that use hydrogenated amorphous silicon parallel-plate capacitors (Al/a-Si:H MS-PPC-LEKIDs), which are under development for the Next-generation Extended Wavelength Multiband Submillimeter Inductance Camera (NEW-MUSIC). We show that, under dark conditions, these devices are generation recombination (GR) noise dominated down to 0.1 Hz and, under optical load, they are likely dominated by GR and photon noise down to tenths of a Hz and possibly lower, both in spite of the use of a-Si:H PPCs. Our measurements set limits on the low-frequency two-level-system (TLS) noise of the a-Si:H material that are consistent with higher frequency measurements in the 0.1-10 kHz regime. These results establish that our MS-PPC-LEKID design for NEW-MUSIC will be photon-noise-limited under a range of observing conditions and, more generally, that a-Si:H PPC-KIDs are a viable new detector technology for even low modulation-rate applications such as astronomy.