Cascade switching current detectors based on arrays of Josephson junctions

Area of Science:

• Condensed Matter Physics
• Superconducting Devices
• Photon Detection

Background:

• Photon detector sensitivity is often enhanced using cascade multiplication.
• Conventional detectors (vacuum tubes, semiconductors) have limited low-frequency performance due to high work functions.
• Superconducting detectors offer a solution for terahertz (THz) and microwave (MW) frequency ranges.

Purpose of the Study:

• To introduce a novel concept for cascade-amplified superconducting detectors.
• To leverage Josephson junction arrays for enhanced signal amplification.
• To demonstrate improved sensitivity and signal-to-noise ratio in MW and THz detection.

Main Methods:

• Developed cascade-amplified superconducting detectors utilizing Josephson junction arrays.
• Employed interjunction coupling to trigger avalanche-like switching upon photon absorption.
• Fabricated and tested prototypes using low-T_c Nb-based and high-T_c BiSCCO intrinsic Josephson junctions.

Main Results:

• Demonstrated cascade amplification of readout voltage in Josephson junction arrays.
• Achieved enhanced signal-to-noise ratio compared to conventional single-junction detectors.
• Confirmed MW and THz response in fabricated detector prototypes.

Conclusions:

• Josephson junction arrays enable cascade amplification for highly sensitive superconducting detectors.
• The developed detectors show significant advantages for broadband MW-to-THz applications.
• This technology holds promise for next-generation sensitive detectors in the MW-THz spectrum.