We have previously analyzed adaptive measurements for estimating the continuously varying phase of a coherent beam, and a broadband squeezed beam. A real squeezed beam must have finite photon flux N and hence can be significantly squeezed only over a limited frequency range. In this paper we analyze adaptive phase measurements of this type for a realistic model of a squeezed beam. We show that, provided it is possible to suitably choose the parameters of the beam, a mean-square phase uncertainty scaling as (N κ)-5 8 is possible, where κ is the linewidth of the beam resulting from the fluctuating phase. This is an improvement over the (N κ)-1 2 scaling found previously for coherent beams. In the experimentally realistic case where there is a limit on the maximum squeezing possible, the variance will be reduced below that for coherent beams, though the scaling is unchanged.
|Number of pages||13|
|Journal||Physical Review A - Atomic, Molecular, and Optical Physics|
|Publication status||Published - 2006|
Bibliographical noteCopyright 2006 by The American Physical Society. Reprinted from Physical review A. Atomic, molecular, and optical physics.
An erratum for this article exists in Physical Review A, vol. 87, issue 1, article no. 019901. DOI: 10.1103/PhysRevA.87.019901