摘要
A scheme for generating sub-Poisson light in a negative feedback and cascade three-level system is proposed in this paper. By using Langevin quantum theory, it is shown that there is a partial correlation between the two output light beams, one of which is fed back to control pump source so that the pump noise may be suppressed. When the pump noise is perfectly suppressed, the photon noise level of the internal field is 50% below the standard quantum limit (SQL), but the reduction of the output photon noise is related with the atomic number N. When N is very large, the output noise level is SQL. When N is very small, the sub-Poisson light can be produced within the cavity bandwidth in the external field, and the fluctuation of output photon flow approaches zero when N approaches 1. The conclusion in this paper is of generality.
A scheme for generating sub-Poisson light in a negative feedback and cascade three-level system is proposed in this paper. By using Langevin quantum theory, it is shown that there is a partial correlation between the two output light beams, one of which is fed back to control pump source so that the pump noise may be suppressed. When the pump noise is perfectly suppressed, the photon noise level of the internal field is 50% below the standard quantum limit (SQL), but the reduction of the output photon noise is related with the atomic number N. When N is very large, the output noise level is SQL. When N is very small, the sub-Poisson light can be produced within the cavity bandwidth in the external field, and the fluctuation of output photon flow approaches zero when N approaches 1. The conclusion in this paper is of generality.
基金
the National Natural Science Foundation of China
