One of the standard tasks of interferometry is binary (yes/no) detection of a given phase shift. Its advantage over the task of measuring an unknown phase shift is the availability of a priori information, which allows for higher sensitivity. The use of non-classical non-Gaussian states of the probing light looks very promising in this case. In this work, we consider an interferometric scheme using the Schrödinger cat (SC) non-Gaussian states, taking into account the non-ideal quantum efficiency of the photodetector. We calculate the achievable sensitivity, assuming the realistic values of quantum efficiency and achievable values of the SC state amplitudes.
42.62.Eh Metrological applications; optical frequency synthesizers for precision spectroscopy
42.87.Bg Phase shifting interferometry
$^1$Moscow Institute of Physics and Technology
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