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Cold-electron bolometers (CEBs) integrated with twin-slot antennas have been designed and fabricated. Optical response was measured at bath temperatures of 0.06 to 3 K using blackbody radiation source at temperatures of 3 to 15 K. The responsivity of 0.3 \ast 10^9\ \V/W was measured at 2.7-K blackbody temperature that is close to the temperature of the cosmic microwave background. Optical measurements indicate quasi-optical coupling efficiency of up to 60% at low phonon temperature and low signal level. Estimations for bolometer responsivity were made for practical range of bath temperatures and blackbody radiation temperatures. The estimated ultimate dark responsivity at 100-mK bath temperature can approach SV =\break 10^{10}\ \V/W and reduces down to 1.1 \ast 10^8\ \V/W at 300 mK for a device with absorber volume of 5 \ast 10^-20\ \m^3. [ABSTRACT FROM PUBLISHER]

Two series/parallel arrays of ten cold-electron bolometers with superconductor–insulator–normal tunnel junctions were integrated in orthogonal ports of a cross-slot antenna. To increase the dynamic range of the receiver, all single bolometers in an array are connected in parallel for the microwave signal by capacitive coupling. To increase the output response, bolometers are connected in series for dc bias. With the measured voltage-to-temperature response of 8.8 \mu\V/mK, absorber volume of 0.08 \mu\m^3, and output noise of about 10 \nV/Hz^1/2, we estimated the dark electrical noise equivalent power (NEP) as \NEP = 6 \ast 10^-18\ \W/Hz^1/2. The optical response down to \NEP = 2 \ast 10^-17\ \W/Hz^1/2 was measured using a hot/cold load as a radiation source and a sample temperature down to 100 mK. The fluctuation sensitivity to the radiation source temperature is 1.3 \ast 10^-4\ \K/Hz^1/2. A dynamic range over 43 dB was measured using a backward-wave oscillator, a variable polarization grid attenuator, and cold filters/attenuators. [ABSTRACT FROM AUTHOR]

We develop a quasiclassical theory of Andreev interferometers with three superconducting electrodes. Provided the tunneling interface resistance between one superconducting electrode and the normal metal strongly exceeds two others, significant current sensitivity to the external magnetic flux is observed only at subgap voltages. If all barrier conductances are comparable, multiple Andreev reflection comes into play and substantial current modulation can be achieved in both subgap and overgap voltage regimes. Our analysis reveals a large variety of interesting features, which can be used for performance optimization of Andreev interferometers. [ABSTRACT FROM AUTHOR]