Cryogenic power sensor enabling broad-band and traceable measurements

Abstract

Recently, great progress has been made in the field of ultrasensitive microwave detectors, reaching even the threshold for utilization in circuit quantum electrodynamics (cQED). However, these cryogenic sensors lack the ability to perform broad-band metrologically traceable power absorption measurements, which limits their scope of applications. Here, we demonstrate such measurements using an ultralow-noise nanobolometer supplemented by an additional direct-current (dc) input. The tracing of the absorbed power relies on comparing the response of the bolometer between radio frequency (rf) and dc heating powers traced through the Josephson voltage and quantum Hall resistance. To illustrate this technique, we demonstrate a fast calibration process of an attenuated input line over more than nine octaves of bandwidth with an rf heating power of −114 dBm and uncertainty down to 0.33 dB.

Propagating quantum microwaves: towards applications in communication and sensing

“…Thus, some further optimization of the graphene bolometer may lead to a convenient device for photon counting for the cQED. In addition to its wide range of applications in photon sensing in general, this device can be modified to detect the heat deposited by a dc current, also allowing one to calibrate for absolute microwave power or possibly low currents at millikelvin temperatures [101].…”

Propagating Quantum Microwaves: Towards Applications in Communication and Sensing

“…Thus, some further optimization of the graphene bolometer may lead to a convenient device for photon counting for the cQED. In addition to its wide range of applications in photon sensing in general, this device can be modified to detect the heat deposited by a dc current, also allowing one to calibrate for absolute microwave power or possibly low currents at millikelvin temperatures [89].…”