Non-classical properties of the single-mode cavity field after interacting with a■-type three-level atom

<正>We study the non-classical properties of the single-mode electro-magnetic field resulting from the interaction of a S-type three-level atom initially in the coherent state,such as squeezing properties and sub-Poisson statistics.We show that if there are more photons in the cavity,the squeezing will appear earlier and be stronger under the same state,but the sub-Poisson statistics will be weaker,while sub-Poisson statistics and squeezing are more pronounced after the selective atomic measurement.