Transfer of Fisher information in quantum postselection metrology

Postselected weak measurement has shown significant potential for detecting small physical effects due to its unique weak-value-amplification phenomenon. Previous works suggest that Heisenberg-limit precision can be attained using optical coherent states. However, the observed Heisenberg scaling requires a measurement of the distribution of postselection probability, exhibiting no implementation pathway through conventional measurement paradigms. Here, we demonstrate that the output photons can also reach the Heisenberg scale by utilizing the Fisher information transfer effect, while this scenario exhibits enhanced robustness against dephasing noise. In addition, we consider the insertion of a power-recycling cavity and demonstrate its positive impact on the distribution of postselection. Our results enhance the quantum metrological advantages of the postselection strategy and broaden its application scope.