Development of dual-polarization LEKIDs for CMB observations

TL;DR

This paper presents the design, fabrication, and initial testing of dual-polarization LEKID arrays optimized for CMB observations, demonstrating promising noise and responsivity performance for future cosmology experiments.

Contribution

It introduces dual-polarization LEKID arrays with two architectures and provides initial characterization data for their application in CMB studies.

Findings

Initial noise spectra and noise-equivalent temperature measurements

Responsivity levels suitable for CMB observations

Successful demonstration of dual-polarization detection in LEKIDs

Abstract

We discuss the design considerations and initial measurements from arrays of dual-polarization, lumped element kinetic inductance detectors (LEKIDs) nominally designed for cosmic microwave background (CMB) studies. The detectors are horn-coupled, and each array element contains two single-polarization LEKIDs, which are made from thin-film aluminum and optimized for a single spectral band centered on 150 GHz. We are developing two array architectures, one based on 160 micron thick silicon wafers and the other based on silicon-on-insulator (SOI) wafers with a 30 micron thick device layer. The 20-element test arrays (40 LEKIDs) are characterized with both a linearly-polarized electronic millimeter wave source and a thermal source. We present initial measurements including the noise spectra, noise-equivalent temperature, and responsivity. We discuss future testing and further design optimizations to be implemented.