Practice question

Modern confocal systems use point illumination from lasers, scanning mirrors, dichroic filters, pinhole apertures for spatial filtering and sensitive point detectors such as photomultiplier tubes or hybrid GaAsP detectors. Image formation relies on sequential photon counting rather than widefield capture by an area array chip. Therefore a conventional charge-coupled device camera, typical of widefield epifluorescence, is not employed for primary imaging in laser-scanning confocal instruments. Spinning-disk confocals may use EMCCD, but classical laser-scanning architecture reconstructs images from detector signals synchronized with scanner position, not CCD exposure.