Bolometer operating at the threshold for circuit quantum electrodynamics

Bolometers operating at low temperatures are promising for detection of itinerant microwave photons and qubit readout. They benefit from a broad detection bandwidth and low dissipation. However, single-microwave-photon sensitivity has not been achieved yet. To address this issue, we experimentally demonstrate an ultrafast bolometer based on a graphene Josephson junction and operating at the threshold of circuit quantum electrodynamics [1]. Graphene, with its unusual thermal properties, offers the opportunity to reach the single-microwave-photon regime. Our device yields a noise equivalent power of 30 zW/rtHz at a thermal time constant of 500 ns and an extracted energy resolution of h×30 GHz.

[1] R. Kokkoniemi et al., Bolometer operating at the threshold for circuit quantum electrodynamics, Nature, 586, 47-51 (2020)