Noiseless Optical Amplification of Images
Sang-Kyung Choi, Michael Vasilyev, Prem Kumar · Physical Review Letters · 1999
We used a spatially broadband optical parametric amplifier for image amplification. In the phase-sensitive configuration of the amplifier, we observed noiseless amplification of input images. For a gain of $\ensuremath{\simeq}2.5$, we measured noise-figure values of ( $0.2\ifmmode\pm\else\textpm\fi{}0.6$) and ( $0.4\ifmmode\pm\else\textpm\fi{}0.5$) dB, respectively, for two amplifiers of different lengths. These experimental values agree with theory (for an ideal noiseless amplifier the noise figure is 0 dB) and are almost 2 dB lower than the quantum limit of an ideal phase-insensitive amplifier.