Enhanced resolution of lossy interferometry by coherent amplification of single photons

We report a proposal which exploits an optical parametric amplification to boost interferometry sensitivity in the presence of losses in a minimally invasive scenario. By performing the amplification process on the microscopic probe after the interaction with the sample, we can beat the losses detrimental effect on the phase measurement which affects the single photon state after its interaction with the sample, and thus improve the achievable sensitivity.