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 detectors' bandwidth. Here, 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 ∼ 25% of temporal quantum noise reduction with respect to the shot-noise limit in images captured by the EMCCD camera. The temporal images captured by our technique are potentially important in obtaining dynamical information on evolving systems.
Spatial quantum correlations in the transverse degree of freedom promise to enhance optical resolution, image detection, and quantum communications through parallel quantum information encoding. In particular, the ability to observe these spatial quantum correlations in a single shot will enable such enhancements in applications that require real-time imaging, such as particle tracking and in situ imaging of atomic systems. Here, we report on measurements in the far field that show spatial quantum correlations in single images of bright twin beams with
108 photons in a 1-$\ensuremath{\mu}\mathrm{s}$ pulse using an electron-multiplying charge-coupled-device camera. A four-wave mixing process in hot rubidium atoms is used to generate narrowband, bright pulsed twin beams of light. Owing to momentum conservation in this process, the twin beams are momentum correlated, which leads to spatial quantum correlations in the far field. We show around 2 dB of spatial quantum noise reduction with respect to the shot-noise limit. The spatial squeezing is present over a large range of total number of photons in the pulsed twin beams.