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Single-Photon Detector: Dead Time & Dark Counts — 2D

Interactive 2D simulator of a single-photon avalanche diode (SPAD): a real Poisson click generator with a real paralyzable/non-paralyzable dead-time gate and dark counts, a live event timeline, and a genuinely-measured count-rate-vs-true-rate curve that shows real dead-time saturation.

Quantum Physics2DModerate60 FPS📱 Mobile-adapted⇄ 3D version

This 2D companion models the same real single-photon avalanche diode (SPAD) as the 3D version — Poisson photon arrivals, a tunable detection efficiency, thermal dark counts, and trap-release afterpulsing — but adds the piece the 3D one leaves implicit: a genuinely-measured count-rate-vs-true-rate curve. Instead of only plotting the textbook dead-time formula, this simulator re-runs its own event-driven generator at dozens of true photon rates, gates every arrival through a real paralyzable or non-paralyzable dead-time window exactly as the live timeline does, and plots what actually came out — the real saturation (non-paralyzable) or roll-off (paralyzable) nonlinearity that limits every SPAD used in quantum key distribution, LIDAR and fluorescence-lifetime imaging.

⚙ Under the hood

Simulate a single-photon avalanche diode (SPAD): Poisson photon arrivals trigger clicks at a tunable quantum efficiency, each followed by a dead-time blind window, while dark counts and afterpulsing add spurious noise clicks on a live 3D timeline.

quantum opticssingle-photon detectorSPADdark countsdead timePoisson process

2D · HTML5 Canvas 2D · 60 FPS target · runs fully client-side, no install