# Beyond conventional photon-number detection with click detectors

## TL;DR

This paper demonstrates that an array of 100 click detectors can significantly extend photon-number measurement capabilities, enabling characterization of quantum states over a much wider intensity range without complex data reconstruction.

## Contribution

The authors introduce a method using a large array of click detectors to surpass traditional photon-number detection limits, bridging the gap between single-photon and linear detection.

## Key findings

- Enhanced intensity range by two orders of magnitude.
- Effective quantum state characterization with click detector arrays.
- No need for complex data reconstruction methods.

## Abstract

Photon-number measurements are a fundamental technique for the discrimination and characterization of quantum states of light. Beyond the abilities of state-of-the-art devices, we present measurements with an array of 100 avalanche photodiodes exposed to photon-numbers ranging from well below to significantly above one photon per diode. Despite each single diode only discriminating between zero and non-zero photon-numbers we are able to extract characteristic information about the quantum state. We demonstrate a vast enhancement of the applicable intensity range by two orders of magnitude relative to the standard application of such devices. It turns out that the probabilistic mapping of arbitrary photon-numbers on a finite number of registered clicks is not per se a disadvantage compared with true photon counters. Such detector arrays can bridge the gap between single-photon and linear detection, by directly using the recorded data, without the need of elaborate data reconstruction methods.