Before revision: The NEFD can be related to a light detector's Noise-Equivalent Power for a collection area A and a photon bandwidth by: , where a factor (often 2, in the case of switching between measuring a source and measuring off-source) accounts for the photon statistics for the mode of operation.
After revision: The NEFD can be related to a light detector's Noise-equivalent power for a collection area A and a photon bandwidth by: , where a factor (often 2, in the case of switching between measuring a source and measuring off-source) accounts for the photon statistics for the mode of operation.