Dual polarization kinetic inductance detectors for large imaging cameras at millimeter wave bands

Abstract

This work deals with the development of superconducting Kinetic Inductance Detectors (KIDs) for highly sensitive radio astronomy receivers within W-band (75 to 110 GHz). A bilayer based on superconducting titanium/aluminum (Ti/Al) thin films has been used for assessing its absorption performance in this frequency band at millikelvin temperature. A lumped-element inductor based on a 4th order Hilbert structure is designed to absorb the incoming radiation in two orthogonal linear polarizations. The development of a large-format camera prototype is presented. On one hand, ambient temperature quasi-optical characterization demonstrates a suitable absorption for both polarizations within the W-band. On the other hand, dark cryogenic characterization confirms the successful operation of the multiplexed KID devices providing high-quality factors and an operation yield of 97%. These results confirm these developments to be used in future polarimeter receivers.