What question did this study set out to answer?

Evaluate the potential of Pb–graphene–Pb Josephson junctions for single-photon detection at millimeter wavelengths.

May 21, 2026MRS Advances0 citationsOpen Access

Electrodynamic simulation of an antenna-coupled Pb–graphene–Pb Josephson junction at millimeter wavelengths

EFEmily FrederickUniversity of Central Florida SBSwastik BallavUniversity of Central Florida JGJavier GonzálezUniversity of Central Florida

Key Points

Evaluate the potential of Pb–graphene–Pb Josephson junctions for single-photon detection at millimeter wavelengths.
Conduct electrodynamic simulations for bowtie antenna design.
Estimate AC current and voltage responsivity associated with Shapiro steps from the junction.
Compare responsivity near critical current with Johnson noise to establish a lower limit for noise equivalent photon flux.
Achieved voltage responsivity of 0.9 MV/W at 300 GHz.
Estimated noise equivalent power is 0.11 fW/√Hz, equivalent to 2 photons per microsecond.

Abstract

Abstract Potential for single-photon mm-wave detection by antenna-coupled Pb–graphene–Pb Josephson junctions (JJ) is evaluated. We consider the high-speed “video” (non-thermal) detection based on Shapiro steps induced by antenna-sourced AC currents across the JJ. Electrodynamic simulation informs the bowtie antenna design and estimates the AC current through JJ. Standard JJ models are used to estimate the corresponding AC voltage and the downward shift of the maximum zero-voltage DC current I c, where a sharp transition occurs in the DC voltage–current curve. Calculated voltage responsivity for current biasing near I c is compared with Johnson noise to estimate a lower limit for noise equivalent photon flux. Estimated responsivity is 0. 9 MV/W M V / W at 300 GHz GHz, and the lower bound on the noise equivalent power is 0. 11 fW/ {Hz} Hz giving a 2 photons per microsecond. Graphical abstract

AIに質問

Bookmark

View Full Paper