Phase super-sensitivity is obtained when the sensitivity in a phase measurement goes beyond the quantum shot noise limit, whereas super-resolution is obtained when the interference fringes in an interferometer are narrower than half the input wavelength. Here we show experimentally that these two features can be simultaneously achieved using a relatively simple setup based on Gaussian states and homodyne measurement. Using 430 photons shared between a coherent and a squeezed vacuum state, we demonstrate a 22-fold improvement in the phase resolution, while we observe a 1.7-fold improvement in the sensitivity. In contrast to previous demonstrations of super-resolution and super-sensitivity, this approach is fully deterministic.
Schäfermeier, C., Ježek, M., Madsen, L. S., Gehring, T., & Andersen, U. L. (2018). Deterministic phase measurements exhibiting super-sensitivity and super-resolution. Optica, 5(1), 60-64. https://doi.org/10.1364/OPTICA.5.000060