Response of a Cold-Electron Bolometer in a coplanar antenna system

TL;DR

This study investigates the performance of cold-electron bolometers integrated with coplanar antennas, demonstrating their response across multiple frequency bands and achieving low noise equivalent power at millikelvin temperatures.

Contribution

It presents new fabrication techniques using aluminum-hafnium technology and characterizes the bolometer response in different frequency ranges at cryogenic temperatures.

Findings

Response at 7-9 GHz and 14 GHz with specific bandwidths.

Achieved NEP below 10 aW/Hz^1/2 at 300 mK.

Response in 0.5-3 GHz range due to aluminum's kinetic inductance.

Abstract

Cold electron bolometers have shown their suitability for use in modern fundamental physical experiments. Fabrication and measurements of the samples with cold-electron bolometers integrated into coplanar antennas are performed in this study. The bolometric layer was made using combined aluminum-hafnium technology to improve quality of aluminum oxide layer and decrease the leakage current. The samples of two types were measured in a dilution cryostat at various temperatures from 20 to 300 mK. The first sample with Ti/Au/Pd antenna shows response in the two frequency bands, at 7--9 GHz with bandwidth of about 20%, and also at 14 GHz with 10% bandwidth. The NEP below 10 aW/Hz^1/2 is reached at 300 mK for 7.7 GHz signal. The second sample with aluminum made antenna shows response in the frequency range 0.5--3 GHz due to the effect of kinetic inductance of superconducting aluminum.