Cryogenic sensor enabling broad-band and traceable power measurements

J. P. Girard, R. E. Lake*, W. Liu, R. Kokkoniemi, E. Visakorpi, J. Govenius, M. Möttönen

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

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Recently, great progress has been made in the field of ultrasensitive microwave detectors, reaching even the threshold for utilization in circuit quantum electrodynamics. However, cryogenic sensors lack the compatibility with broad-band metrologically traceable power absorption measurements at ultralow powers, which restricts their range of applications. Here, we demonstrate such measurements using an ultralow-noise nanobolometer, which we extend by an additional direct-current (dc) heater input. The tracing of the absorbed power relies on comparing the response of the bolometer between radio frequency and dc-heating powers traced to the Josephson voltage and quantum Hall resistance. To illustrate this technique, we demonstrate two different methods of dc-substitution to calibrate the power that is delivered to the base temperature stage of a dilution refrigerator using our in situ power sensor. As an example, we demonstrate the ability to accurately measure the attenuation of a coaxial input line between the frequencies of 50 MHz and 7 GHz with an uncertainty down to 0.1 dB at a typical input power of −114 dBm.

Original languageEnglish
Article number054710
Pages (from-to)1-11
Number of pages11
JournalReview of Scientific Instruments
Issue number5
Publication statusPublished - 1 May 2023
MoE publication typeA1 Journal article-refereed


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