Parametric Amplification of Images: From Time Gating to Noiseless Amplification

Image parametric amplification and its applications are reviewed in this paper. Phase matching conditions allow the resolution to be determined and spatial frequency filtering to be performed. The phase conjugate idler image can be used to cancel aberrations. Then, time gating properties are applied to ultrafast imaging, imaging through diffusing media, and lifetime fluorescence imaging. Degenerate schemes permit polychromatic amplification as well as phase-sensitive amplification, which is proved to be noiseless with respect to spatial fluctuations at the quantum level. Finally, it is shown that the spatial fluctuations of the signal and the idler are subshot noise correlated.