A detector system described in a November 12 report can count from zero to more than 9,000 individual photons, extending the range of photon-number measurements. The researchers’ clearest quantified precision result is more specific: for laser pulses containing up to 276 photons, measurement uncertainty was smaller than one photon. That distinction matters when assessing what the system has demonstrated.
The work, by a team that included Timon Schapeler and Tim Bartley of Paderborn University, combines superconducting nanowire single-photon detectors with multiplexing. The paper is listed as Timon Schapeler et al., “Macroscopic photon counting beating the Poisson noise limit,” published in Optica in 2026.
Counting individual photons becomes harder as their number grows. The report explains that common single-photon detectors such as avalanche photodiodes typically register whether photons arrived, rather than how many. Detectors used for large numbers of photons can face a different problem: electrical noise can obscure differences in photon number. Superconducting nanowire detectors can resolve photon numbers and are known for high efficiency, precise timing and low noise, but resolving only a limited number of photons had been demonstrated previously.
The new system uses multiplexing to spread the light from one pulse across many detection opportunities. The researchers split each pulse into 128 smaller pulses separated in time, then distributed those among eight detectors. Together, these produced 1,024 detection bins containing portions of the original pulse. The approach combines the photon-number resolution of the detectors with the wider measurement range provided by multiplexing.
A model of the individual detector elements was another part of the method. The report says the researchers used model-informed characterization of each bin to account for how the elements respond. That helped them determine photon numbers precisely: for measurements up to 276 photons, uncertainty was below one photon. According to the report, a conventional multiplexed system would need about 37,000 detector elements to reach the same precision, compared with the new system’s 1,024 bins.
The report also describes a broader counting range, from zero to more than 9,000 photons. To study the detector’s response under different conditions, the team sent laser pulses with average photon numbers ranging from one to 15,000. Those input averages should not be confused with the reported sub-photon uncertainty result: the specific precision benchmark is stated for measurements up to 276 photons. The report does not spell out how precision was established across the full range above that benchmark.
The motivation is to make large-scale measurements of individual photons more practical as photonic quantum systems grow. Photon counting is relevant to photonic quantum computing and imaging that is sensitive to single photons, both areas identified in the report as possible beneficiaries. Bartley said the technology could help researchers learn how such systems might be scaled. That is a prospect, rather than a report that the detector has already enabled a larger quantum computer or camera.
The present study applied the system to laser pulses. The researchers plan to apply it to bright quantum states of light, which could help reveal quantum effects at larger scales. The report also points to possible future sensing uses as the detector technology improves. These applications remain future directions; the reported measurements establish a detector approach and its performance on laser pulses.