Deterministic phase measurements exhibiting super-sensitivity and super-resolution

10^th International Conference and Exhibition on Lasers, Optics & Photonics

November 26-28, 2018 | Los Angeles, USA

Clemens Schafermeier

Attocube systems AG, Germany

Posters & Accepted Abstracts: J Laser Opt Photonics

Abstract :

Phase measurements by optical interferometry is a ubiquitous tool, with applications ranging from biological studies, over profiling surfaces, to sensing gravitational waves for fundamental research. A cornerstone in the achievable accuracy of interferometry, and metrology, in general, was then set by quantum mechanics: due to Heisenberg�??s uncertainty relation, a definite limit of the measurement�??s accuracy was found. In retrospective, Heisenberg�??s finding was challenged in various ways ever since, either by preparing the input in ways only accessible by quantum mechanics or by measuring the output with �??non-classical�?� techniques. Achievements of these attempts are techniques which enhance the measurement of phase changes, referred to as supersensitivity and super-resolution. More precisely, 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 verify experimentally that these two features can be simultaneously achieved using a relatively simple setup (sketched in figure 1) 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 (refer to figure 2). In contrast to previous demonstrations of super-resolution and super-sensitivity, this approach is fully deterministic. Finally, we attempt to resolve a long-standing debate about the actual usefulness of super-resolution by simulations. Here we find that super-resolution in settings where Gaussian noise dominates, super-resolution offers no benefits over other techniques.

Biography :

E-mail: clemens@fh-muenster.de