Dc SQUID near the quantum noise limit

Dale J. Van Harlingen, Roger H. Koch, John Clarke

Research output: Contribution to journalArticlepeer-review


A series of dc SQUIDs has been fabricated in an attempt to obtain quantum-limited sensitivity. Typically, the SQUID inductance, L, is 2 pH, the capacitance and critical current of each tunnel junction are 0.5 pF and 0.5 mA, and the shunt resistance for each junction is 1Ω. The measured spectral density of the voltage noise Sv contains a 1/f component that extends typically to 100 kHz or higher. When the 1/f component is subtracted out, the best energy sensitivity achieved to date is ε 1Hz = Sv 2L( ∂V ∂Φ)2 2 ̌ h {combining short stroke overlay}, where ∂V/∂Φ is the transfer coefficient.

Original languageEnglish (US)
Pages (from-to)1083-1084
Number of pages2
JournalPhysica B+C
Issue number1-3
StatePublished - 1981
Externally publishedYes

ASJC Scopus subject areas

  • Engineering(all)


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