Single-photon detectors
Photon counting resolves faint optical signals beyond analog intensity measurement.
$$P(\mathrm{click})=1-e^{-\eta\mu}$$
Physical intuition
Photon counting resolves faint optical signals beyond analog intensity measurement.
Deep dive: physical mechanism
Detector efficiency maps incident photon statistics to click events; dark counts and dead time modify the likelihood.
What is measured experimentally?
Count distributions and timing histograms quantify weak light.
Assumptions, noise and limitations
Threshold detectors do not resolve photon number without additional architecture.
Research and simulation exercise
Infer photon flux from click rates including dark counts.
Connect the ideas
Explore the chapter overview, learning path, and references.