Ultimate low system dark-count rate for superconducting nanowire single-photon detector

Area of Science:

• Quantum optics
• Photonics
• Superconducting devices

Background:

• The dark-count rate (DCR) is a critical performance metric for single-photon detectors.
• High DCR can limit the sensitivity and accuracy of photon detection systems.

Purpose of the Study:

• To suppress the dark-count rate (DCR) of a superconducting nanowire single-photon detector (SNSPD).
• To improve the overall performance and figure of merit of SNSPDs.

Main Methods:

• Implementation of a bulk optical band-pass filter on a fiber-to-fiber optical bench.
• Cooling the setup to 3 K to minimize thermal noise.
• Blocking infrared radiation below 5 μm.

Main Results:

• Achieved a DCR suppression of over three orders of magnitude.
• Reduced DCR from 10⁻³ Hz to 10⁻⁴ Hz by narrowing the bandwidth to 100 GHz.
• Improved the figure of merit to 1.8×10¹².

Conclusions:

• Optical filtering and cryogenic cooling are effective strategies for reducing DCR in SNSPDs.
• Narrowing the optical bandwidth significantly enhances detector performance.
• The improved SNSPD performance opens possibilities for more sensitive quantum measurements.