Squeezed-state enhanced two-frequency interferometry

Here an experiment is proposed to demonstrate squeezed-state enhanced interferometry. An interferometer employing differenced detection, in which the photodetectors have less than a unit quantum efficiency, is analyzed. In order to avoid low-frequency noise, a readout signal at frequency 2v8 is generated at the detector by injecting coherent light having two frequency components v_o + v_s, and v_o - v_s, into one input port of the interferometer. In order to realize a significant sensitivity enhancement, squeezed light fed into the other input port must be squeezed at frequencies v_o ±v_s and v₀ ± 3_vs.