EMCCD Tutorial
Q5 How sensitive are EMCCDs?
Two parameters significantly influence detector sensitivity—quantum efficiency (QE)
and noise floor. QE is a measure of a camera’s ability to capture valuable photons.
A high QE results in more photons being converted to photoelectrons within the CCD
pixels. Once converted, the photoelectrons in a given pixel must overcome the detection
limit or noise floor of the camera, which is set by the system noise. EMCCDs deliver
superior sensitivity by maximizing QE through front and back-illuminated sensors
(the latter delivering up to 95% QE), and minimizing system noise floor, through
elimination of read noise and TE cooling of darkcurrent. Single photon events are
now well within the capabilities of super sensitive EMCCD technology.