Plate Nº 50 · recorded November 13, 2026
PhysicsReported finding
New Detector System Counts More Than 9,000 Individual Photons
Paderborn researchers built a 1,024-bin detector system that counts up to 9,000-plus photons, measuring pulses of 276 photons with uncertainty below a single photon.
By Elena Vasquez4 min read772 words
In brief
- The system counts from zero to more than 9,000 individual photons using 1,024 detection bins.
- It measured pulses of up to 276 photons with uncertainty smaller than one photon; a conventional system would need ~37,000 elements for the same precision.
- The work combines SNSPDs with multiplexing at an order of magnitude larger scale than previous systems.
- Published in Optica (2026), DOI: 10.1364/optica.604389, by Timon Schapeler et al. of Paderborn University.
A new detection system can precisely count from zero to more than 9,000 individual photons, an advance that opens new possibilities for studying quantum light at large scales and making precise optical measurements. Researchers at Paderborn University in Germany published the work in the journal Optica.
The system combines superconducting nanowire single-photon detectors (SNSPDs) with a technique called multiplexing to create 1,024 detection bins — separate slots that each register a share of the incoming light. Used together with a model-based characterization of every bin, it measured light pulses containing up to 276 photons with an uncertainty smaller than a single photon. A conventional multiplexed setup would need roughly 37,000 detector elements to match that precision. The Paderborn team needed 1,024.
That's the headline: sub-photon accuracy at an order of magnitude beyond earlier systems.
Why counting photons gets hard
"Precisely counting photons becomes more challenging as their numbers increase," said Timon Schapeler of Paderborn University. "Our approach extends photon counting to larger numbers of photons, bridging the gap between single-photon measurements and high-sensitivity optical power meters."
The problem sits in the middle of the photon-number range. Common single-photon detectors, such as avalanche photodiodes, typically report only whether photons are present or absent — not how many. Photodiodes and similar devices that handle large photon numbers carry significant electrical noise, which drowns out the ability to resolve individual photons.
Photon-number-resolving detectors, including SNSPDs, offer a third path. They distinguish between different numbers of arriving photons, and they bring high efficiency, very high timing resolution and low noise. Recent work showed these detectors can resolve a limited photon count through high-precision timing measurements.
"We wanted to know how high we can push the number of photons that can be counted with SNSPDs," Schapeler said. The answer: a system that merges multiplexing with the intrinsic photon-number resolution of the detectors themselves. Both technologies had been studied separately before, but nobody had demonstrated the combination at this scale — an order of magnitude larger than previous multiplexed single-photon counting systems.
How the system works
Multiplexing mimics photon-number resolution by spreading light across many detector elements. The researchers split one incoming light pulse into 128 smaller pulses separated in time. They then split those onto eight different detectors, producing 1,024 individual smaller pulses carrying the original photon count divided among them.
"Our approach uses low-loss optical components to distribute light evenly across 1,024 detection bins while preserving photon-number information in each bin," said Tim Bartley of Paderborn University. "This enables precise measurements, while multiplexing expands the range of photon numbers the system can measure."
A second ingredient mattered just as much: a detector model the researchers had previously developed with Mariia Sidorova of PTB, Germany's national metrology institute. The model accurately describes each individual detector element in the overall system, and that accuracy drove the precision of the final measurements.
Each piece does one job. Multiplexing stretches the counting range; the model keeps the numbers honest.
What did the tests show?
The researchers sent laser pulses with average photon numbers between one and 15,000 per pulse into the device. That range let them probe how the detector responds under different conditions and pin down the precision with which it counts photons in a pulse.
The result: photon counting of up to 276 photons with measurement uncertainties below one photon, thanks to the accuracy of the detector model. The headline figure of more than 9,000 photons refers to the full counting range the system can span — from zero up to that ceiling.
What comes next?
"Large-scale measurement of individual photons is a cornerstone of photonic quantum computing and single-photon-level imaging," Bartley said. "With this new macroscopic photon-counting technology, we can learn a lot about how photonic quantum computers and single-photon-sensitive cameras can be scaled."
As photonic quantum systems grow, building and analyzing sufficiently large detection systems will become increasingly important — and that's exactly the gap this work targets.
The current study applied SNSPDs only to laser pulses. Next, the researchers plan to turn the system on bright quantum states of light, which could reveal quantum effects at large scales. As SNSPD technology continues to improve, the detector system could enable precise, highly sensitive measurements across a range of sensing applications.
The takeaway: a detector that counts photons one by one, at scales where nobody has counted them before.
Publication details: Timon Schapeler et al., "Macroscopic photon counting beating the Poisson noise limit," Optica (2026). DOI: 10.1364/optica.604389.
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Correspondent covering money, funding and market shifts around general science news at SciBeat.
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