Response of a cold-electron bolometer in a coplanar antenna system

Abstract Cold-electron bolometers have shown suitability for use in modern fundamental physical experiments. In this study, the fabrication and measurements of the samples with cold-electron bolometers integrated into coplanar antennas are performed. The absorber layer was made using combined aluminum-hafnium technology to improve quality of aluminum oxide layer and decrease electron–phonon coupling. 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 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msqrt> <mml:msup> <mml:mrow> <mml:mi>Hz</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> </mml:msqrt> </mml:mrow> </mml:math> 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.