Experimental demonstration of the relative phase operator

Abstract

We have experimentally demonstrated a realization of the two-mode relative phase operator introduced by Luis and Sánchez-Soto (Luis A and Sánchez-Soto L L 1993 Phys. Rev. A 48 4702). The relative phase distribution function was measured for a weakly excited relative phase eigenstate and weakly excited two-mode coherent states. The experiment is also (using the eigenstates) a demonstration of Heisenberg-limited interferometry.