Researchers at the National Institute of Standards and Technology (NIST) have developed a new superconducting single-photon detector architecture that utilizes wires more than 100 times wider than conventional devices while improving current flow and sharply reducing false signals, according to The Quantum Insider.
Superconducting Nanowire Single-Photon Detectors
Superconducting nanowire single-photon detectors (SNSPDs) are used to capture photons for applications such as quantum computing, deep-tissue imaging, transmitting data in quantum networks, deep space communication links, building biomedical images, and searching the universe for dark matter. Traditional SNSPDs typically rely on highly specialized nanometer-scale fabrication techniques and use a 100-nanometer-wide wire made of superconducting material connected to a readout circuit. While NIST has previously improved these devices to detect 98% of incoming photons, fabrication defects and detector edges have historically capped maximum current flow and performance.
NIST Superconducting Rails and Magnetic Field
To overcome these challenges, NIST researchers sized up the superconducting wires to a tenth of a millimeter—more than 100 times wider than typical SNSPDs—simplifying the detector’s design and fabrication. The new design incorporates superconducting “rails” that border the central wire and run current in the same direction, generating a magnetic field. This allows wider wires to redistribute electrical current across the detector, operate closer to their intrinsic performance limits, and remain sensitive to low-energy photons.
Photons carry information,
said Kristen Parzuchowski, a postdoctoral researcher at NIST. Whenever a photon comes into your measurement system, you need to be able to detect it.
Kristen Parzuchowski on Minimizing Wire Dimensions
Commenting on the traditional approach of minimizing wire dimensions, Parzuchowski noted, Typically, everyone has worked to make smaller and smaller wires, which makes fabrication increasingly challenging.
Eli Mueller, a NIST postdoctoral researcher, explained that scientists previously believed superconducting wires in SNSPDs needed to be nanoscale so that a single particle of light could create a tiny splash in the electric current across the entire width of the wire to break superconductivity. By operating closer to the transition between the superconducting state and the normal state, the new architecture maintains sensitivity to very low-energy photons while increasing wire width.
