Tolerance enhancement of inefficient detection and frequency detuning by non-perfect phase-sensitive amplification in broadband squeezing-based precision measurement

Phase-sensitive amplification (PSA) can significantly improve the degradation caused by inefficient detectors in squeezing-based precision measurements. However, broadband incident light will lead to non-perfect PSA. The present work focused on the enhancement of non-perfect PSA for squeezed states with broad bandwidth for the measurement of weak absorption detection. Numerical calculations of the quantum advantage show that non-perfect PSA can effectively improve the inefficiency of detection in slight drift frequency detuning.