Photon shot noise
= Photon shot noise
Independent photon arrivals have a <Poisson distribution>: a mean count $\mu$ has variance $\mu$ and standard deviation $\sqrt\mu$. Subtraction of independent counting measurements adds their variances.
= Photon shot noise
Independent photon arrivals have a <Poisson distribution>: a mean count $\mu$ has variance $\mu$ and standard deviation $\sqrt\mu$. Subtraction of independent counting measurements adds their variances.