  Electron-multiplying charge-coupled-device cameras (EMCCDs) have been used to
observe quantum noise reductions in beams of light in the transverse spatial
degree of freedom. For the quantum noise reduction in the temporal domain,
"bucket detectors," usually composed of photodiodes with operational
amplifiers, are used to register the intensity fluctuations in beams of light
within the bandwidth of the detectors. Spatial information, however, is
inevitably washed off by the detector. In this paper, we report on measurements
of the temporal quantum noise reduction in bright twin beams using an EMCCD
camera. The four-wave mixing process in an atomic rubidium vapor cell is used
to generate the bright twin beams of light. We observe more than 25% of
temporal quantum noise reduction with respect to the shot-noise limit in images
captured by the EMCCD camera. Compared with bucket detectors, EMCCD makes it
possible to take advantage of the spatial and temporal quantum properties of
light simultaneously, which would greatly benefit many applications using
quantum protocols.
