Design of Dual-Polarization Horn-Coupled Kinetic Inductance Detectors for Cosmic Microwave Background Polarimetry

TL;DR

This paper introduces a new design for dual-polarization Kinetic Inductance Detectors (KIDs) optimized for cosmic microwave background polarization measurements, emphasizing scalability, simplicity, and compatibility with existing fabrication techniques.

Contribution

The paper presents a novel dual-polarization KID design with simplified fabrication and readout, suitable for large-scale arrays in CMB polarization studies.

Findings

Design achieves near photon-noise-limited performance

Detectors are compatible with standard fabrication processes

Arrays can be built efficiently using conventional machining

Abstract

Mapping the polarization of the Cosmic Microwave Background is yielding exciting data on the origin of the universe, the reionization of the universe, and the growth of cosmic structure. Kilopixel arrays represent the current state of the art, but advances in detector technology are needed to enable the larger detector arrays needed for future measurements. Here we present a design for single-band dual-polarization Kinetic Inductance Detectors (KIDs) at 20% bandwidths centered at 145, 220, and 280 GHz. The detection and readout system is nearly identical to the successful photon-noise-limited aluminum Lumped-Element KIDs that have been recently built and tested by some of the authors. Fabricating large focal plane arrays of the feed horns and quarter-wave backshorts requires only conventional precision machining. Since the detectors and readout lines consist only of a single patterned aluminum layer on a SOI wafer, arrays of the detectors can be built commercially or at a standard university cleanroom.