Design of deeply cooled ultra-low dissipation amplifier and measuring cell for quantum measurements with a microwave single-photon counter
Oleg G. Turutanov, A. M. Korolev, V. I. Shnyrkov, Andrii P. Shapovalov, Martin Baránek, Samuel Kern, V. Yu. Lyakhno, P. Neilinger, M. Grajcar · Low Temperature Physics · 2024
The requirements and details of designing a measuring cell and low-back-action deeply-cooled amplifier for quantum measurements at 10 mK are discussed. This equipment is a part of a microwave single-photon counter based on a superconducting flux qubit. The high-electron mobility transistors (HEMTs) in the amplifier operate in unsaturated microcurrent regime and dissipate only 1 μW of dc power per transistor. Simulated amplifier gain is 15 dB at 450 MHz with a high-impedance (≈ 5 kΩ) signal source and standard 50-Ω output.