Reconstruction of squeezing by a three-level quantum filter

Abstract

It is shown that a three-level system with suitable values of electromagnetic coupling between the levels is capable of absorbing the photon of a one-photon state in a squeezed mode but not of the photons of the two-photon state in this same mode, allowing reconstruction of the squeezing of a previously squeezed state degradated by losses. Also a dissipative version is proposed in which the intermediate level is coupled to a continuum which dumps out the oscillation due to the filter precessions. © 1994.