Intense development of nanobolometers has taken place for well more than a decade with the aim to reach noise equivalent power NEP = 10e-20 W/rtHz. Furthermore, observation of single photons at increasingly long wavelengths is a long-standing effort. We present a microwave nanobolometer based on superconductor/normal-metal/superconductor Josephson junctions. Using positive electrothermal feedback, we show that we can achieve a single-shot detection ?fidelity of 0.56 for 1.1-zJ pulses of 8.4-GHz photons . This is more than an order of magnitude improvement over the previous thermal detectors. Furthermore, we observe that we can reach NEP = 2*10e-20 W/rtHz with our detector in the linear bolometric mode . The measured frequency dependence of the NEP suggest that this bolometer is capable of detecting single 0.3-zJ photons. These results were achieved by integrating the bolometer with a quantum-limited Josephson parameteric apmli?er and further improvements are expected for example using two-dimensional materials.
 J. Govenius, R. E. Lake, K. Y. Tan, and M. Möttönen, Phys. Rev. Lett. 117, 030802 (2016).
 R. Kokkoniemi et al., arXiv:1806.09397 (2018).
|Less than 5 years of experience since completion of Ph.D||N|
|Student (Ph.D., M.Sc. or B.Sc.)||N|