National Institute of Standards and Technology (NIST) researchers have achieved 98% photon detection using improved superconducting nanowire single-photon detectors (SNSPDs), a significant advance for sensitive applications like biomedical imaging and deep-space communication, the company says. These SNSPDs capture photons by disrupting electric current; each detected photon creates an electric pulse registering the light’s impact.
Kristen Parzuchowski, a postdoctoral researcher at NIST, emphasized the importance of detecting every particle for technologies ranging from quantum computing to dark matter searches. The team enlarged detector wires to a tenth of a millimeter, over 100 times wider than typical designs, simplifying fabrication and unlocking improved performance.
98% Photon Detection Achieved with Scaled-Up NIST Detectors
Achieving 98% photon detection, NIST researchers have overcome a longstanding limitation in superconducting nanowire single-photon detector (SNSPD) technology. This simplification of fabrication unlocks a higher potential performance previously obscured by manufacturing challenges. Scientists previously believed maximizing sensitivity required nanoscale wires, reasoning that a photon’s energy needed to disrupt superconductivity across the entire wire width.
Eli Mueller, a NIST postdoctoral researcher, explained this thinking: “Your photon energy needs to break superconductivity over the entire width of the wire,” he said. “It’s very difficult to have your device in a regime where the photon could break superconductivity over 100 microns wide, so devices needed to be on the order of hundreds of nanometers wide.” However, operating at such small scales limited current flow, hindering the detection of lower-energy photons and introducing unwanted “dark counts” from electrical noise. To address this, the team implemented superconducting rails alongside the central wire, redistributing current and eliminating edge buildup.
This innovative approach allows for significantly higher current flow, generating a more pronounced signal from each photon, according to NIST. “If we can get the middle of our device to flow more current than what was previously accessible, then we can generate a hot spot over an arbitrarily wide wire. And that hot spot is what’s giving you the pulse out,” Mueller elaborated. The wider detectors also exhibit polarization insensitivity, meaning they can detect photons regardless of the orientation of their electric field.
The team has now shown that the intrinsic performance limit can be reached. Beyond the 98% efficiency, the team recorded a billion-fold reduction in dark counts, a result Parzuchowski described as promising for applications ranging from biomedical imaging to astronomical observation, where detecting even the faintest light signals is crucial.
There are many applications where you’re working with handfuls of photons. Ideally, you need to detect all of them.
Kristen Parzuchowski, a postdoctoral researcher at the National Institute of Standards and Technology
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